These cam edge clamps offer high holding forces and easy to use handle operation. Turning the handle forces the serrated jaw forward and downward against the workpiece. Easily installs with a socket head cap screw. The body and jaw are made from heat-treated 4140 alloy steel, with a black oxide finish. The cam and handle are made from 4135 alloy steel with a black oxide finish. The ball knob is made from black plastic.