4 x 4-1/8" Precision Mill Vise Specification: Dimensions Jaw Width: 4" Jaw Opening: 3.93" Jaw Height: 1-1/4" Accurate to 0.002" per 4" on squareness and 0.006" per 4" on parallelism without base and 0.008" per 4" on parallelism with base Vise Key: 11.11mm table slot width, 14.00mm base width Base Swivel: 360-degree Features: -Each pound of force in horizontal induces 1/2 lb of downward force, eliminating jaw tilt. This Vise is so designed that the horizontal force generated by tightening the handle pushes the semi-sphere within the movable jaw and thus thrusts the movable jaw downward. The workplace does not move up, even if it is held at the top of the jaw plates. -The precise 360-degree scale help to adjust any position as you need. Greatly increased flexibility of use. -Highest clamping power. It's very accurate and durable. -Sliding surface of the vise bed is flame hardened and ground. -Vise bed is made from grey cast iron and the maximum tensile strength of the vise bed is 28,000 PSI With anti-jaw lifting mechanism. K type angle lock nut is made from the highest quality ductile Iron, firm and durable. - The adjustable handle with a comfortable grip makes it easy to operate and improves efficiency. -Acme screws and easy to read 0-360 deg scales. -4 screws from the top through the jaw reduce key's side force and make the vise body not easy to broke, extend vise life. Package Included: 1 x 4 Inch Precision Mill Vise 1 x Accessory Set