ChuPower 4 1/2" Bench Vise CT-105Jaw opening size: 4 1 2" The vise body is made from heavy duty cast iron for high hardness and durability. Vise jaws are made of 45# steel with diamond shape grooves which provide more clamping force in order to keep workpiece more stable during machining. Surface is finished by power coating which makes the vice beautiful, durable and easy to clean dirt and oil. The vise includes a small anvil on the back of its body.