Creedmoor Sports Caliper Anvil Calipers are the handloaders friend, and they are used to constantly check several critical features during the handloading process. However sometimes it can be a bit tricky to balance a cartridge square on the lower caliper jaw. This is where the Caliper Anvil can help. It securely attached to the bottom jaw via a thumb screw provide a wide and stable circle where you can place the base of the cartridge squarely on the bottom jaw. This is especially helpful when you are using it with a datum tool. Features: A 3/4 in 416 Stainless Steel Construction Mounts easily to the lower or upper jaw of a 0-6 or 0-8in calipers Brass thumb screw quickly and securely attaches anvil to caliper.