VG6 Precision EPSILON 556SL Muzzle Brake 5.56x45mm NATO 0.745 inch Diameter Nitride Black. 5" rifle builds. Featuring an outside diameter of .745" the EPSILON 556SL can be pinned and welded to your barrel while still allowing full maintenance and removal of your gas block without having to remove the muzzle device. The EPSILON 556SL utilizes a new aggressive chamber design that improves gas flow and reduces felt recoil significantly. It also features deep channel cuts that greatly reduce the overall weight toward the front end of your build. Slim in design does not mean slim in performance. Users can still expect the same great performance they have grown to trust from VG6 Precision muzzle brakes. With the EPSILON 556SL you have the optimal solution for a lightweight legal (when pinned and welded) and flat shooting 14.5" Rifle Build. Specifications for VG6 Precision EPSILON 556SL Muzzle Brake: Manufacturer: VG6 Precision Color: Black Caliber: 5.56x45mm NATO Finish: Nitride Gun Model: AR-15 Length: 2.21 in Weight: 1.6 oz Condition: New Diameter: 0.745 in Country of Origin: USA Package Contents: VG6 Precision EPSILON 556SL Muzzle Brake What firearm models does the manufacturer say VG6 Precision EPSILON 556SL Muzzle Brake is compatible with? The manufacturer says that VG6 Precision EPSILON 556SL Muzzle Brake is compatible with AR-15VG6 Precision APVG100025A: EPSILON 556SL Muzzle Brake 5.56x45mm NATO 0.745 inch Diameter Nitride Black