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Polarstar Kythera SA V2.5 (A&K/JG/SR-25)

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PolarStar Precision Airsoft Components (PPAC) was formed in January 2009 to fill the need for precision engineered airsoft upgrade parts. PPAC is a division of PolarStar Engineering & Machine (PSE&M), a unique blend of tenured American toolmakers and a full service CAE/CAD/CAM (Computer Aided Engineering, Design, and Manufacturing), special crafts machine shop keeping alive our proud manufacturing heritage of "Made in the USA".

Founded in 1997, PSE&M specializes in servicing the automotive racing industry by designing and engineering systems and components from "art to part." Whether a unique one off prototype up to and including manufacturing large quantities of finished and tested parts and assemblies. Operating under the auspices of the Delaware Association of Professional Engineers, we retain a Professional Engineer (P.E.) on staff to ensure and certify all design and engineering standards are met.

The Kythera from Polarstar answers the question: How do I get HPA without batteries? The Kythera utilizes a mechanical system to open and release air from the poppet, eliminating the need for electrical power. It utilizes the mechanical principles from things like striker fired rifles and pneumatic tools to give you a precise semi-auto operation without the need for fancy electronics.

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 semi-auto only, The Kythera still retains the same performance and quality you have come to expect from PolarStar products, while removing the electronic compenents.

The Kythera uses a mechanical only operation, which also gives you a realistic feeling trigger. This mechanical action is perfect for MILSIM enthusiasts or CQB players that have no need for a full auto setting. Charging batteries has become a thing of the past with Kythera.

Just like all other PolarStar HPA conversions, Kythera 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 rifles velocity in increments of just a few FPS at a time. Maximum velocity potential of the system will vary depending upon the barrels length and tightness of the bore. Longer and tighter barrels will yield a higher velocity while shorter or wider barrels will be yield a lower velocity.

Key Features

Manufacturer: PolarStar Airsoft
Model: Kythera
Muzzle Velocity: 280 - 500 FPS, Adjustable
Rate of Fire:Semi-only
PSI Operating Range: 60 - 180 PSI
Package Includes: Kythera and trigger linkage.


  • Made in the U.S.A.
  • Adjustable Velocity
  • Mechanical Operation
  • Center Line Nozzle Design
  • Universal Cylinder Design is Compatible with Numerous Gearbox Versions

Manufacturer: PolarStar
see 1 reviews | Write a Review
verified buyer
W. MARTINEZ | 2021-08-04
Product Information:
Excellent performance. I love that its mechanical cause i only shoot semi auto so this was a no brainer easy to install solution to maximize performance.


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