Gray Casting Iron Jaw width: 4 inch , Mix opening:4.33 inch Hardened steel jaw Professional designed for woodworking, metalworking, sawyer, drilling, and gluing assistanty installation: easy to install on workstation Easy installation: easy to install on workstation Please use it on drilling and milling machine Tools By Rolin Drill Press Vise 4” Light Duty Workbench. The package does not contailn screws