This ERGO Armorer Block is one of the most useful maintenance accessories available for an AR-15. Simply bolt or clamp securely to a bench or other work surface place an AR rifle onto the block inside the magazine well and the rifle is held in place for cleaning maintenance or storage. - 1-piece rugged design - Weight: 4.3oz - 6 1/8 Tall X 4 5/16 Long (at the Base) X 2 Wide (at the Base) - 1/4 Mounting Holes