Birchwood Casey AR-15 Lower Receiver Vise Block Grey. Clamps in any vise allowing easy access for cleaning / assembly? CNC construction for precise fitment? Soft jaw design will not mar the receiver? Includes snap pits for secure engagement to the receiver? Allows user to install and torque down the barrel to the receiver Package Contents: Birchwood Casey AR-15 Lower Receiver Vise Block Snap pits What firearm models does the manufacturer say Birchwood Casey AR-15 Lower Receiver Vise Block is compatible with? The manufacturer suggests that Birchwood Casey AR-15 Lower Receiver Vise Block is compatible with AR-15Birchwood Casey Vise Block For AR-15 Lower Receiver