Strike Industries Mass Driver 9mm Luger Glock 19 Gen 4 Compensator - The Strike Industries Mass Driver compensator represents a quantum leap in compensator design. The Mass Driver Compensator is driven by the hot gasses expelled through the barrel after the round is discharged, and acts as a counter balance system to attenuate mechanical recoil. Barrel mounted compensators add reciprocating mass and increase the moment of inertia to the operating system, which can have a negative effect on reliable cycling of recoil operated handguns.