InLine Fabrication also STOCKS the quick change top plate for the Viper barrel vise right (Here) The Viper Barrel Vise is constructed of 6061 aluminum. The bottom half is 1” thick, for added strength, when mounting to your work bench. All four hardened, threaded bolts have a support spring. These springs keep the top half from moving around during barrel insertion and removal. Each spring is fully captured on each end for stability. SPECS: Base is 7" x 3" with 5 3/4" c-t-c hole spacing for mounting; top plate is 3" square; four 1/2" bolts for clamping; and will accommodate 0.77" to 1.3" OD barrels. UPC 700358214011