This quick-adjust vertical surface hold down clamp allows you to secure work tightly to your workbench anywhere you can drill 3/4 inch dog holes. The 1-1/2 inch long post is just shy of 3/4 inch, so will slip in and out of any 3/4 inch dog hole. The post has machined serrations along its length so when the handle is turned and pressure applied, the post wedges tightly in a hole and will not slip. This clamp will work in tops as thin as 3/4 inch thick. The unbreakable cast zinc base is 1-1/2 inches in diameter and 1-1/2 inches tall. The base and post are black coated to resist corrosion. <br> <br> The moveable clamp jaw slides easily along the serrated rail and then locks down tight when the handle is tightened offering slip-resistant clamping. The jaw is made from reinforced malleable steel and provides powerful and rigid clamping. The serrated carbon steel rail has an hourglass profile to resist flexing and twisting. <br> <br> The moveable jaw features smooth-turning carbon steel Acme threads and can generate up to 600 pounds of clamping pressure. The screw end has a 1 inch diameter swivel pad with a non-marring clamp pad to allow gripping of odd- shaped parts. Overall spindle travel is 2 inches. Threads are black coated to resist corrosion. The ergonomic soft grip Plastic/TPR handle optimizes torque and reduces hand fatigue. Will clamp parts up to 4 inches thick.