AR-15 Colt USGI A2 5.56x45 flash hider (USGI A2)
The 5.56x45 Colt USGI A2 flash hider (a.k.a. Bird Cage) is designed for mounting on 5.56x45 weapons built on the AR-15 system. However, it can be installed on other weapons of the same caliber provided that barrel has the same threading for muzzle devices. A service muzzle device for M4A1.