Birchwood Casey AR-15 Upper Receiver Vise Block Grey. It installs to upper receiver on standard AR-15 or equivalent rifles. Specifications for Birchwood Casey AR-15 Upper Receiver Vise Block: Manufacturer: Birchwood Casey Gun Model: AR-15 Gun Make: AR Platform Gun Type: Rifle Caliber: 5.56mm Fabric/Material: CNC Color: Gray Condition: New Features of Birchwood Casey AR-15 Upper Receiver Vise Block Installs to upper receiver on standard AR-15 or equivalent rifles 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 pins for secure engagement to the receiver Allows user to install and torque down the barrel to the receiver Package Contents: Birchwood Casey AR-15 Upper Receiver Vise Block Snap pits What firearm models does the manufacturer say Birchwood Casey AR-15 Upper Receiver Vise Block is compatible with? The manufacturer suggests that Birchwood Casey AR-15 Upper Receiver Vise Block is compatible with AR-15Birchwood Casey UPPRVISE-BLOCK: AR-15 Upper Receiver Vise Block Grey