{"title":"HPA Parts","description":null,"products":[{"product_id":"polarstar-kythera-hpa-engine-model-sa-ver2-m4","title":"Polarstar \"Kythera\" HPA Engine (Model: SA - Ver2 M4)","description":"\u003ch4\u003eFeatures\u003c\/h4\u003e\n\u003cul class=\"productfeatures\"\u003e\n\u003cli\u003eDesigned from the ground up as a high performance mechanical HPA system, not a modification of a solenoid operated design\u003c\/li\u003e\n\u003cli\u003ePatent pending valve mechanism provides excellent efficiency and consistent velocity combined with a realistic trigger pull and reset\u003c\/li\u003e\n\u003cli\u003eCompletes a full shot cycle on the trigger pull alone which translates into consistent nozzle movement and rapid follow up shots\u003c\/li\u003e\n\u003cli\u003eAdjustable trigger. Adjustments include: Weight, length of pull and over travel\u003c\/li\u003e\n\u003cli\u003eAdjustable nozzle dwell\/return speed\u003c\/li\u003e\n\u003cli\u003eWide operating pressure range of 60 to 180psi\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThe Kythera has been the most eagerly anticipated products from PolarStar in the past decade. This HPA system is a radical departure from all previous systems that PolarStar has produced since the Kythera does not use a battery, an FCU or any type of electronics. The Kythera is completely mechanical. This means you never have to worry about charging batteries or work with delicate electronics. It also means that the system is completely waterproof.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eThe name \"Kythera\" (ky-the-ra) was derived from the Antikythera Mechanism which is a mysterious device that was discovered by sponge divers off the coast of the Greek island Antikyther. The mechanism was so advanced in design that scientists have been studying it for decades to discover its purpose. The machine dates from around the end of the 2nd century B.C. and is the most sophisticated mechanism known from the ancient world. Nothing as complex is known for the next thousand years. The Antikythera Mechanism is now understood to be dedicated to astronomical phenomena and operates as a complex mechanical \"computer\" which tracks the cycles of the Solar System.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"UTF-8\"\u003eFor this reason we used the name Kythera for the valve mechanism at the core of a new line of PolarStar mechanical HPA systems. Although it contains very few parts and is easy to install and maintain, the system incorporates a very intelligent design and is unlike anything else on the market. The system was designed as a mechanical system from the ground up and uses a realistic trigger mechanism which can be applied to single, semi-automatic and fully-automatic systems.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eRealistic Trigger:\u003c\/b\u003e What sets this system apart from other mechanical systems is the design of its trigger. The trigger mechanism is designed to replicate the function, weight and feel of a real single-action trigger. It feels real because it is real. The hardened alloy steel sears catch and release the stainless steel spool valve in the same way the sears of a real firearm catch and release the hammer or striker. This gives the Kythera trigger the distinct break and reset you would expect to feel when firing a real single action device. The trigger mechanism in the Kythera SA is also adjustable, allowing the user to fine tune the weight and over travel. Additionally, the internal firing valve is balanced and the only force applied during firing is the main spring. This means the function and feel of the trigger is independent of input pressure and velocity.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eComplete Shot Cycle:\u003c\/b\u003e The design of the Kythera SA completes a shot cycle on the trigger pull. This gives you the proven closed bolt performance of the Fusion Engine and F2 in a completely mechanical, waterproof system with a realistic trigger. It does not require the trigger to be released before the nozzle chambers the next round and the firing volume is refilled. This occurs automatically and consistently every shot, with adjustable nozzle dwell and return speed.\u003cbr\u003eAs the system resets and recharges immediately after firing, it is ready to fire again before the trigger has been released. This means the system can cycle very quickly for faster follow up shots and a lower potential for double feeding.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eExtremely Efficient and Consistent:\u003c\/b\u003e The valve design of the Kythera operates without the need for air to control the opening or closing of the valve. Without a pilot valve, 100% of the air going into the system is fired through the nozzle allowing it to operate very efficiently. In addition to being extremely efficient, the system is also extremely consistent. The valve is released at the same point every shot with the same force applied, regardless of trigger input.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eUniversal Charging Cord:\u003c\/b\u003e The steel cord visible at the back of the system is attached to a cocking mechanism for the internal spool valve. Although the system automatically cocks the spool valve when the system is pressurized, since the Kythera uses a balanced valve, it is possible in certain situations that the valve could stall and needs to be manually cocked. This typically only happens if the system is run completely out of air so that the pressure drops below the operating range of the system. The cord is designed to be either routed through the grip of the rifle for easy access or even possibly attached in some fashion to the charging handle.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"UTF-8\"\u003e \u003cb\u003eEasy Installation:\u003c\/b\u003e The Kythera SA system installs into a standard gearbox as a single assembly and typically does not require any modification to the gearbox. There are no separate parts to install and the only parts needing to be retained from the gearbox is the trigger, spring guide, selector and safety components.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eWide Velocity Adjustment Range:\u003c\/b\u003e The Kythera has a wide operating pressure range of 60psi to 180psi which allows you to fine tune the velocity of the system and tailor for different requirements and applications. Within this pressure range we observed a muzzle velocity of 270 - 500fps w\/ .20g using a 6.05x380mm barrel. This lets a single Kythera be used in any role ranging from CQB to Sniper by mainly just adjusting the input pressure from your air rig.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cbr\u003e\u003c\/span\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e PolarStar Airsoft\u003c\/p\u003e","brand":"Evike Inc.","offers":[{"title":"Default Title","offer_id":48459140825310,"sku":"19157","price":399.99,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0748\/9146\/0830\/files\/Screenshot2026-07-21at10.45.35PM.png?v=1784699476"},{"product_id":"polarstar-kythera-hpa-engine-model-sa-a-k-sr-25","title":"Polarstar \"Kythera\" HPA Engine (Model: SA - A\u0026K SR-25)","description":"\u003ch4\u003eFeatures\u003c\/h4\u003e\n\u003cul class=\"productfeatures\"\u003e\n\u003cli\u003eDesigned from the ground up as a high performance mechanical HPA system, not a modification of a solenoid operated design\u003c\/li\u003e\n\u003cli\u003ePatent pending valve mechanism provides excellent efficiency and consistent velocity combined with a realistic trigger pull and reset\u003c\/li\u003e\n\u003cli\u003eCompletes a full shot cycle on the trigger pull alone which translates into consistent nozzle movement and rapid follow up shots\u003c\/li\u003e\n\u003cli\u003eAdjustable trigger. Adjustments include: Weight, length of pull and over travel\u003c\/li\u003e\n\u003cli\u003eAdjustable nozzle dwell\/return speed\u003c\/li\u003e\n\u003cli\u003eWide operating pressure range of 60 to 180psi\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThe Kythera has been the most eagerly anticipated products from PolarStar in the past decade. This HPA system is a radical departure from all previous systems that PolarStar has produced since the Kythera does not use a battery, an FCU or any type of electronics. The Kythera is completely mechanical. This means you never have to worry about charging batteries or work with delicate electronics. It also means that the system is completely waterproof.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eThe name \"Kythera\" (ky-the-ra) was derived from the Antikythera Mechanism which is a mysterious device that was discovered by sponge divers off the coast of the Greek island Antikyther. The mechanism was so advanced in design that scientists have been studying it for decades to discover its purpose. The machine dates from around the end of the 2nd century B.C. and is the most sophisticated mechanism known from the ancient world. Nothing as complex is known for the next thousand years. The Antikythera Mechanism is now understood to be dedicated to astronomical phenomena and operates as a complex mechanical \"computer\" which tracks the cycles of the Solar System.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eFor this reason we used the name Kythera for the valve mechanism at the core of a new line of PolarStar mechanical HPA systems. Although it contains very few parts and is easy to install and maintain, the system incorporates a very intelligent design and is unlike anything else on the market. The system was designed as a mechanical system from the ground up and uses a realistic trigger mechanism which can be applied to single-shot, semi-automatic and fully-automatic systems.\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"UTF-8\"\u003e\n\u003cb\u003eRealistic Trigger:\u003c\/b\u003e What sets this system apart from other mechanical systems is the design of its trigger. The trigger mechanism is designed to replicate the function, weight and feel of a real single-action firearm trigger. It feels real because it is real. The hardened alloy steel sears catch and release the stainless steel spool valve in the same way the sears of a real firearm catch and release the hammer or striker. This gives the Kythera trigger the distinct break and reset you would expect to feel when firing a real single action firearm. The trigger mechanism in the Kythera SA is also adjustable, allowing the user to fine tune the weight and over travel. Additionally, the internal firing valve is balanced and the only force applied during firing is the main spring. This means the function and feel of the trigger is independent of input pressure and velocity.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eComplete Shot Cycle:\u003c\/b\u003e The design of the Kythera SA completes a shot cycle on the trigger pull. This gives you the proven closed bolt performance of the Fusion Engine and F2 in a completely mechanical, waterproof system with a realistic trigger. It does not require the trigger to be released before the nozzle chambers the next round and the firing volume is refilled. This occurs automatically and consistently every shot, with adjustable nozzle dwell and return speed.\u003cbr\u003eAs the system resets and recharges immediately after firing, it is ready to fire again before the trigger has been released. This means the system can cycle very quickly for faster follow up shots and a lower potential for double feeding.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eExtremely Efficient and Consistent:\u003c\/b\u003e The valve design of the Kythera operates without the need for air to control the opening or closing of the valve. Without a pilot valve, 100% of the air going into the system is fired through the nozzle allowing it to operate very efficiently. In addition to being extremely efficient, the system is also extremely consistent. The valve is released at the same point every shot with the same force applied, regardless of trigger input.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eUniversal Charging Cord:\u003c\/b\u003e The steel cord visible at the back of the system is attached to a cocking mechanism for the internal spool valve. Although the system automatically cocks the spool valve when the system is pressurized, since the Kythera uses a balanced valve, it is possible in certain situations that the valve could stall and needs to be manually cocked. This typically only happens if the system is run completely out of air so that the pressure drops below the operating range of the system. The cord is designed to be either routed through the grip of the rifle for easy access or even possibly attached in some fashion to the charging handle.\u003cbr\u003e\u003cbr\u003e\u003cb\u003eEasy Installation:\u003c\/b\u003e The Kythera SA system installs into a standard gearbox as a single assembly and typically does not require any modification to the gearbox. There are no separate parts to install and the only parts needing to be retained from the gearbox is the trigger, spring guide, selector and safety components.\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cspan\u003e\u003cmeta charset=\"UTF-8\"\u003e\n\u003cb\u003eWide Velocity Adjustment Range:\u003c\/b\u003e The Kythera has a wide operating pressure range of 60psi to 180psi which allows you to fine tune the velocity of the system and tailor for different requirements and applications. Within this pressure range we observed a muzzle velocity of 270 - 500fps w\/ .20g using a 6.05x380mm barrel. This lets a single Kythera be used in any role ranging from CQB to Sniper by mainly just adjusting the input pressure from your air rig.\u003cbr\u003e\u003cbr\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e PolarStar Airsoft\u003c\/p\u003e","brand":"Evike Inc.","offers":[{"title":"Default Title","offer_id":48459163435230,"sku":"19158","price":449.99,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0748\/9146\/0830\/files\/Screenshot2026-07-21at11.31.24PM.png?v=1784701949"},{"product_id":"polarstar-kythera-sa-nozzle-type-1","title":"Polarstar Kythera SA Nozzle (Type: #1)","description":"\u003ch4\u003eFeatures\u003c\/h4\u003e\n\u003cul class=\"productfeatures\"\u003e\n\u003cli\u003eDrop in nozzle for PolarStar Kythera HPA engines\u003c\/li\u003e\n\u003cli\u003eBrass construction\u003c\/li\u003e\n\u003cli\u003eModel number designations note which common weapons platforms will work best with your set up\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eFor cylinder conversion systems we assign numbers to the nozzles instead of using the rifle model. This is because the nozzle length can vary between the same gun model when made by different manufacturers. This can be from the manufacturer designing the rifle differently, or from the thickness of the gearbox shell affecting how far from the hop-up chamber the cylinder sits. Therefore one nozzle length may work in different models but not necessarily work in the same model from a different manufacture. For example, a standard MP5 could require any of 4 different nozzle lengths depending on the manufacturer.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eFor this reason we produce numerous different nozzle lengths to provide compatibility for a wide range of replicas. Below we are listing the make and model of the replicas which the nozzle length is most commonly used with but it may be compatible with more models. For a list of replicas which we have measured and calculated the compatible nozzle length, please review chart (picture #2).\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eOnce you determine what number nozzle your replica requires, that number is universal across all engines* that use the numbered nozzle system. So, if you determine your replica takes a #11 JACK nozzle, then it will also take a #11 Kythera or F2 nozzle if you ever put a different system into it. \u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003e*NOTE: The Kythera models which are made for a specific devices (e.g. A\u0026amp;K\/JG SR-25) with a non-standard length cylinder will use a specific nozzle with a \"K\" prefix. Since they use a non-standard cylinder, the universal nozzle numbing system cannot be used for these models. However, the design and profile of the \"K\" nozzles are the same as the standard numbered nozzles and are cross compatible between standard and non-standard cylinders.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eAdditionally, all nozzles are marked with their number with the exception of the #1 nozzle. These are produced in far greater quantities than all of the other nozzles so they are left unmarked to reduce production time.\u003c\/span\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e PolarStar\u003c\/p\u003e","brand":"Evike Inc.","offers":[{"title":"Default Title","offer_id":48459187355870,"sku":"22809","price":39.99,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0748\/9146\/0830\/files\/Screenshot2026-07-21at11.59.18PM.png?v=1784703693"},{"product_id":"polarstar-kythera-sa-nozzle-type-k1","title":"Polarstar Kythera SA Nozzle (Type: #K1)","description":"\u003ch4\u003eFeatures\u003c\/h4\u003e\n\u003cul class=\"productfeatures\"\u003e\n\u003cli\u003eDrop in nozzle for PolarStar Kythera HPA engines\u003c\/li\u003e\n\u003cli\u003eBrass construction\u003c\/li\u003e\n\u003cli\u003eModel number designations note which common weapons platforms will work best with your set up\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eFor cylinder conversion systems we assign numbers to the nozzles instead of using the rifle model. This is because the nozzle length can vary between the same gun model when made by different manufacturers. This can be from the manufacturer designing the rifle differently, or from the thickness of the gearbox shell affecting how far from the hop-up chamber the cylinder sits. Therefore one nozzle length may work in different models but not necessarily work in the same model from a different manufacture. For example, a standard MP5 could require any of 4 different nozzle lengths depending on the manufacturer.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eFor this reason we produce numerous different nozzle lengths to provide compatibility for a wide range of replicas. Below we are listing the make and model of the replicas which the nozzle length is most commonly used with but it may be compatible with more models. For a list of replicas which we have measured and calculated the compatible nozzle length, please review chart (picture #4).\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eOnce you determine what number nozzle your replica requires, that number is universal across all engines* that use the numbered nozzle system. So, if you determine your replica takes a #11 JACK nozzle, then it will also take a #11 Kythera or F2 nozzle if you ever put a different system into it. \u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003e*NOTE: The Kythera models which are made for a specific devices (e.g. A\u0026amp;K\/JG SR-25) with a non-standard length cylinder will use a specific nozzle with a \"K\" prefix. Since they use a non-standard cylinder, the universal nozzle numbing system cannot be used for these models. However, the design and profile of the \"K\" nozzles are the same as the standard numbered nozzles and are cross compatible between standard and non-standard cylinders.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eAdditionally, all nozzles are marked with their number with the exception of the #1 nozzle. These are produced in far greater quantities than all of the other nozzles so they are left unmarked to reduce production time.\u003c\/span\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e PolarStar\u003c\/p\u003e","brand":"Evike Inc.","offers":[{"title":"Default Title","offer_id":48459196465374,"sku":"22824","price":43.99,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0748\/9146\/0830\/files\/Screenshot2026-07-22at12.17.03AM.png?v=1784704672"},{"product_id":"polarstar-gearbox-shim-set-for-cylinder-conversion-kits-size-0-157","title":"Polarstar Gearbox Shim Set for Cylinder Conversion Kits (Size: 0.157\")","description":"\u003ch4\u003eFeatures\u003c\/h4\u003e\n\u003cul class=\"productfeatures\"\u003e\n\u003cli\u003eBrass construction\u003c\/li\u003e\n\u003cli\u003eAids with securing HPA engine inside your gearbox and prevents the engine from moving around\u003c\/li\u003e\n\u003cli\u003eDesigned to fit easily in most common gearboxes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThese sets of precision shims are used to secure an HPA cylinder within the gearbox shell to prevent unwanted movement. Since the pins in a gearbox shell can vary in size depending on the manufacturer, we have to make the matching holes in our cylinder conversion kits large enough to accommodate the largest diameter pins. This can sometimes allow the cylinder to shift backwards or forwards in gearboxes with smaller diameter pins if the shell does not clamp onto the cylinder firmly enough to secure it.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eIf the cylinder is able to move during operation then it can change how far the nozzle extends from the front of the gearbox. This can result in inconsistent BB seating and air seal which can diminish performance.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eThe shims are available in different sizes to match the most common gearbox pin sizes and are compatible with all PolarStar cylinder conversions kits (F2, F1, JACK, Kythera).\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e PolarStar\u003c\/p\u003e","brand":"Evike Inc.","offers":[{"title":"Default Title","offer_id":48459202560222,"sku":"25644","price":16.99,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0748\/9146\/0830\/files\/Screenshot2026-07-22at12.24.59AM.png?v=1784705188"},{"product_id":"polarstar-gearbox-shim-set-for-cylinder-conversion-kits-size-0-152","title":"Polarstar Gearbox Shim Set for Cylinder Conversion Kits (Size: 0.152\")","description":"\u003ch4\u003eFeatures\u003c\/h4\u003e\n\u003cul class=\"productfeatures\"\u003e\n\u003cli\u003eBrass construction\u003c\/li\u003e\n\u003cli\u003eAids with securing HPA engine inside your gearbox and prevents the engine from moving around\u003c\/li\u003e\n\u003cli\u003eDesigned to fit easily in most common gearboxes\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan\u003eThese sets of precision shims are used to secure an HPA cylinder within the gearbox shell to prevent unwanted movement. Since the pins in a gearbox shell can vary in size depending on the manufacturer, we have to make the matching holes in our cylinder conversion kits large enough to accommodate the largest diameter pins. This can sometimes allow the cylinder to shift backwards or forwards in gearboxes with smaller diameter pins if the shell does not clamp onto the cylinder firmly enough to secure it.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eIf the cylinder is able to move during operation then it can change how far the nozzle extends from the front of the gearbox. This can result in inconsistent BB seating and air seal which can diminish performance.\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003cspan\u003eThe shims are available in different sizes to match the most common gearbox pin sizes and are compatible with all PolarStar cylinder conversions kits (F2, F1, JACK, Kythera).\u003c\/span\u003e\u003cbr\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e PolarStar\u003c\/p\u003e","brand":"Evike Inc.","offers":[{"title":"Default Title","offer_id":48459213144286,"sku":"25645","price":16.99,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0748\/9146\/0830\/files\/Screenshot2026-07-22at12.31.54AM.png?v=1784705524"}],"url":"https:\/\/dsgairsoft.ca\/collections\/hpa-parts.oembed","provider":"DSG Airsoft ","version":"1.0","type":"link"}