Prometheus EG Barrel 407mm for M4A1/ SR16/ SG551+

Prometheus EG Barrel 407mm for M4A1/ SR16/ SG551+ For M4A1/ SR16/ SG551+ Airsoft Electric Gun (AEG) Rifle High grade precision barrel at 6.03mm diameter for extra power and precision shooting Choose this barrel to suit your AEG model For custom upgrade user, you can choose a longer barrel PROMETHEUS EG Barrel by LAYLAX (JAPAN) NOTE: You can always choose a longer Barrel if you have a extended Outer barrel installed