This B&T Brass Catcher fits all versions of the SIG SG 550/551/552/553 that use a B&T handguard. It can be attached to and detached from the weapon's Picatinny/NAR rail in seconds using the proven QD mount. For safety checks, it can easily be flipped forward 90 degrees after releasing the locking lever. For SIG 550/551/552/553
