The SureFire ProComp 556 muzzle brake, which fits M4/M16 weapons and variants with 1/2-28 muzzle threads, greatly reduces both recoil impulse and muzzle rise so that the weapon tracks straight back to keep you on target for faster shot-to-shot recovery. Its patented Impulse Diffusion design minimizes side blast and rear-directed concussion effects. The ProComp 556 duplicates the design of the SureFire SOCOM SFMB-556-1/2-28 muzzle brake, but unlike the latter it cannot be used to mount SureFire SOCOM suppressors. Precision machined from US mill-certified steel bar stock-including high-precision cut threads for optimum thread interface-the ProComp 556 muzzle brake has a black Me Mfg: Surefire SPECS: Machined from bar stock steel. Black Melonite finish. Fits 1/2-28 tread pitch.