The full metal Classic Army M15A4 is essentially the same as the M4A1 but has a solid stock in place of the extendable stock. The AEG comes complete with a 300 round high capacity magazine. The metal flash hider can be screwed off revealing a standard 14mm reverse thread, just like the Tokyo Marui M4A1. The Armalite range from Classic Army all come engraved with an individual serial no. and metal hop-up chamber. Dust cover can be flipped open to reveal hop-up adjuster.