Description
The heavy spring is what comes standard in Fusion Engine and F2 HPA systems. It is also the “extra” spring that comes with the Kythera system.
The heavy spring is what comes standard in Fusion Engine and F2 HPA systems. It is also the “extra” spring that comes with the Kythera system.
Brad Hughson (verified owner) –
Awesome little upgrade to the Kythera. Also is very cheap to get a quick and easy increase in FPS. Highly recommend