The Wolfpack Armory Night Howler Recessed Gen 3 now has improved compatibility with other manufacturers mounts. Designed to minimize overall length and gap between handguard and HUB adapter. Compatible with Plan B and Rearden type tapered mounting systems. FeaturesReduces muzzle flashExternal wrench flats allow removal of the muzzle device in the event of carbon lockCNC Machined from 17-4 PH stainless steel H900Depth into silencer with lp Hub Adapter: 1.57"Minimum length difference between barrel and handguard: 1" (16" barrel with 15" handguard, 11.5" barrel with 10.5" handguard, ect.)Maximum gas block journal size: 0.750"Max bore hole size: 0.45"