Magpul BEV BLOCK for AR15/M4, 873750000145, MAG536

•(Barrel Extension Vise) is an all-in-one compact vise block tool for AR15/M4 assembly operations of barrel nuts flash hiders etc. •Mounts securely in vise & provides support for both billet and forged upper receivers •Engages barrel extension w/solid steel lugs & full length support shank to prevent flexing •Steel hardness is optimized for durability wont damage barrel extension and Magpul Polymer is used for all other engagement surfaces to protect aluminum receiver •O-ring post uses bolt carrier for additional stability & included Pin keeps upper in proper position •Can also be turned over & used as a mag well vise block to support the lower receiver during maintenance etc.