{"product_id":"polarstar-fusion-engine-hpa-kit","title":"PolarStar Fusion Engine™ HPA Drop-In Conversion Kit","description":"\u003cp\u003eThe Fusion Engine™ was released in 2011 as the first new HPA system to hit the airsoft market in over two decades — the system that started the HPA revolution and set the benchmark all others are measured against. Winner of \"Best HPA Engine\" the very first year Popular Airsoft added the HPA class to their Players' Choice Awards.\u003c\/p\u003e\n\n\u003cp\u003eThis complete drop-in system replaces the entire AEG gearbox with a full CNC-machined lightweight aluminum chassis. As a dual solenoid, closed bolt system, the poppet valve (firing air) and nozzle (feeding) are independently adjustable, giving you full control over loading time and air volume. PolarStar Filter Fitting included.\u003c\/p\u003e\n\n\u003ch4\u003eWhy Closed Bolt?\u003c\/h4\u003e\n\u003cp\u003eTrue closed bolt operation makes high accuracy easier to achieve since hop-up configuration is less critical than on open bolt systems. The trigger micro-switch is custom fit to the frame, delivering a distinct break, hard stop, and short reset for the best trigger feel of any system PolarStar produces.\u003c\/p\u003e\n\n\u003ch4\u003eGel Ball Compatible\u003c\/h4\u003e\n\u003cp\u003eFusion Engine conversion kits can be configured for gel ball systems. Contact us for details.\u003c\/p\u003e\n\n\u003ch4\u003ePerformance\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eVelocity:\u003c\/strong\u003e 550fps w\/ .20g @ 120psi — 6 nozzles available to shift velocity range up or down in large increments\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eROF:\u003c\/strong\u003e 30rps+ in most standard configurations\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eAir Efficiency:\u003c\/strong\u003e 400+ shots from 13\/3000 @ 1.5J w\/ .28g (can be more than doubled with fine tuning)\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOperating Pressure:\u003c\/strong\u003e Widest adjustment range of any PolarStar system\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"PolarStar","offers":[{"title":"V2 GEN3, M4\/M16","offer_id":45868775014434,"sku":"10000434","price":505.0,"currency_code":"USD","in_stock":true},{"title":"V2 GEN3, M4\/M16 – Red LFP\/Red NZ","offer_id":45868775047202,"sku":"10000707","price":505.0,"currency_code":"USD","in_stock":true},{"title":"M249","offer_id":45868775079970,"sku":"10000994","price":510.0,"currency_code":"USD","in_stock":true},{"title":"M240","offer_id":45868775112738,"sku":"10000995","price":510.0,"currency_code":"USD","in_stock":true},{"title":"M60 (A\u0026K)","offer_id":45868775145506,"sku":"10000996","price":515.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0741\/5355\/8050\/files\/ChatGPT_Image_Jun_19_2026_10_25_48_PM_5.png?v=1781933188","url":"https:\/\/www.katechairsoft.com\/products\/polarstar-fusion-engine-hpa-kit","provider":"KA Tech Airsoft ","version":"1.0","type":"link"}