Size 2-1/4" Weight 3.75 Max. Opening 2-1/4" Min. Opening 0" Depth 1-7/8" Screw Dia. 3/4" Test Load 12,500 Lbs. Weight Per Box 3-3/4 Lbs. Frame is forged from high-strength, heat-treated steel. Large diameter screws are full length and hardened to prevent bending and protect threads. Clamp strengths exceed test loads shown. Conforms to Federal Specification GGG-C-406D, Type 1, Class B, heavy service.