These medium duty German Style adjustable F clamps are the perfect clamping solution for the professional, serious hobbyist or DIYer. They feature reinforced malleable steel jaws that provide powerful and rigid clamping. Jaws are baked-powder coated to resist corrosion. The moveable jaw easily slides along the rail and then locks tight on the serrated rail via the 2 plate clutch system to offer slip-resistant clamping. Clutch plates are hardened steel for long life. The 3/4 inch x 1/4 inch serrated carbon steel rail resists flexing and torsional forces. Both jaws come equipped with clamp pads to prevent marring of delicate workpieces. The moveable jaw features a smooth-turning carbon steel screw that produces maximal clamping pressure with less effort. The screw end has a swivel pad to allow gripping of various shaped parts. Both the steel rail and screw are nickel plated to prevent corrosion. The ergonomic soft grip Plastic/TPR handle optimizes torque and reduces hand fatigue. Maximal clamping force: 450 pounds