Yankee Hill Machine 5M2QD: YHM\'s Phantom Compensator/Brake is for users who desire a muzzle brake instead of a flash hider. The three (3) chamber design has no downward facing ports which helps eliminate dust signature when shooting in the prone position as well as acting as a compensator. It has a smooth sleek look which eases cleaning and also features an improved mounting service which makes attachment quicker, and easier. A shim kit is include with two (2) 0.002\