Our Brownells A1 Ejection Port Cover is an accurately detailed replica of the cover used on M16A1 and earlier rifles - basically the Vietnam Era guns. Unlike the standard A2 cover still in use today, the A1 has a smaller, rectangular finger pad with crisp 90 degree edges. On the inner side, an early-style hexagonal housing retains the catch detent and spring, rather than the simpler, easier to manufacture cylindrical housing of the A2 cover. Aside from these physical details, the Brownells A1 Ejection Port Cover operates and installs just like the covers on modern-day rifles. It's made of stamped steel (not plastic - of course!), with a classic matte dark gray Parkerized finish t Mfg: Brownells