Product code: NUP-06-11 Main spring for normal AEG type rifles. Approx. 490fps Actual power will vary from gun to gun and the above fps should be used as a guide
Product code: NUP-04-01 Improves Firmness of the chamber & stabilizes the muzzle velocity Enhanced Hop-Up Bucking for Accuracy Also, fit tightly to the barrel base to keep the chamber being centered