Kythera Ver. 2 HPA Engine for M4/M16 Polarstar

Kythera Ver. 2 HPA Engine for M4/M16 Polarstar

 Fusion Engine Gen. 3 For M4/M16 -PolarStar

Fusion Engine Gen. 3 For M4/M16 -PolarStar

Jack HPA Engine M4/M16 Version 2 Polarstar

Availability: In stock
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The JACK™ system was designed to answer the demand for an affordable, high-performance HPA (High-Pressure Air) conversion for AEGs. The system is a drop-in cylinder replacement that is universally compatible with a wide range of gearbox versions that have center-line nozzles. Similar to its sister product, the F1, it replaces the original gearbox components with a programmable pneumatic system allowing for higher performance and greater reliability over a gear-driven system. Although economically priced, JACK™ still retains the same performance and quality you have come to expect from PolarStar products. JACK™ has only 1 moving part, the nozzle, which acts as its own poppet valve which is piloted by the solenoid. Except for the poppet being integral to the nozzle, the valve is similar to the poppet valve used in the previously released Fusion Engine™ and is what gives JACK™ its signature muzzle report. The system itself only has 6 parts and can be completely disassembled by hand in a matter of seconds so the system is very reliable and easy to maintain. Just like all other PolarStar HPA conversions, JACK™ also allows for easy velocity adjustment. Using a standard M4 as an example, velocity can be adjusted from below 280fps and up to approximately 500fps with a .20g BB. This can be done simply by adjusting input pressure and poppet dwell to fine-tune your rifle's velocity in increments of just a few FPS at a time. The maximum velocity potential of the system will vary depending on the barrel's length and the tightness of the bore. Longer and tighter barrels will yield a higher velocity while shorter or wider barrels will yield a lower velocity. As with all of PolarStar's electro-pneumatic conversion kits, you can quickly change and adjust key functions of JACK™ via the on-board FCU (Fire Control Unit) which is no bigger than an AEG's MOSFET and can easily fit inside a rifles battery compartment along with a small Li-po battery. Using the FCU's five-position joystick and LCD display you will be able to easily and precisely adjust such functions as the system cyclic rate, fire modes, and poppet dwell on the fly. Although efficiency was not a critical requirement during development, JACK™ does boast some highly respectable figures in this category. This is made possible by its compact and intelligently laid out design which minimizes dead volume resulting in better airflow, faster response, and less air used per shot. As a result, JACK™ is considerably more air efficient than a bone-stock Fusion Engine™ when operating in the same velocity range. HPA system not included


  • Designed, manufactured, and built in the U.S.A.
  • Assembled from CNC machined aluminum components with high-performance Delrin nozzle
  • Universal cylinder design is compatible with numerous gearbox versions
  • Optimized flow profile, firing point, and flow path promotes superior shot consistency and accuracy
  • Capable of functioning in damp and sub-freezing climates without affecting performance or reliability
  • User-selectable Semi/Full Auto, Semi Auto Only, and Variable Burst modes
  • Independently adjustable velocity and cyclic rate
  • Auto Switch mode allows for proper selector configuration for specific models
  • Easy-to-use Fire Control Unit (FCU) with LCD display and five-position joystick
  • Instantaneous trigger response. Faster than an AEG with a LiPo


  • Material:  Aluminum / Delrin
  • Compatibility:  Tokyo Marui Spec Version 2 Gearboxes
  • Included Nozzle Type: M4 / M16 Series
  • Rate of Fire: 1 - 30+ RPS (Adjustable)
  • Muzzle Velocity: 500 FPS w/ .20g 6mm BB @ 120 PSI
  • Fire Modes: Semi / 2 - 9 Round Burst, Semi / Full Auto, Semi Only
  • Power Source: HPA (High-Pressure Air via Remote Air Rig)
  • FCU Battery: 7-10VDC w/ JST Connector
  • PSI Operating Range:  40 PSI - 130 PSI (Do NOT exceed 130 PSI, otherwise you may damage the internals)
  • Package Includes:  Pre-Assembled JACK Conversion Kit
  • Battery: 7.4v-9.6v NiMH or Lipo (Not included).
  • Manufacturer:  PolarStar Airsoft

Required for Operation: -Complete TM Spec AEG rifle with gearbox, Regulated Air Rig, HPA Tank, and Battery (Sold Separately)

Installation: - JACK™ will be installed into the shell of your AEG's gearbox. The only parts which you need to retain from your gearbox is the trigger w/ spring, safety assembly, and selector components. Retain the original spring guide for models which require that the stock be secured to the gearbox and not the receiver.

Compatibility Disclaimer: - The Version 2 - M4/M16 kit is compatible with most TM Spec AEGs in that rifle series. This kit is compatible with other TM Spec rifles which use a Version 2 gearbox with the traditional open contact trigger switch. In most cases, only a model-specific nozzle is required to install the system into another model (i.e. M4 to MP5). If your rifle has an electronic micro switch (i.e. Ares Amoeba) you will need to purchase the kit for that specific model series which will include a different switchboard.

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