ZWQ S400 2.0 Upgrade Spring

Want higher FPS for your S400 blaster?

ZWQ has come up with their own 2.0 Upgrade spring to give your S400 Blaster a much needed FPS boost.

Allowing the blaster to hit at about 305 FPS on average.

NOTE!!!: Please do be careful when trying to change the main springs of the S400 ESPECIALLY when changing the 2.0 Spring.