Beam clamps provide a strong support on angle or flat bar steel surfaces. They are made of malleable iron and have a hot dipped galvanized finish. Beam clamps come with either a 1/2" or 3/8" hardened steel, zinc plated set screw. Each clamp has two additional threaded mounting holes (3/8-16 UNC or 1/2-13 UNC) for additional hardware attachment. 1/2" beam clamps have a 1-1/8" jaw opening and the 3/8" beam clamps have a 1" jaw opening.