Armstrong 78-031 3-5/16" C-Clamp Heavy Duty Pattern
Armstrong's 3-5/16" C-Clamp Heavy Duty Pattern is the strongest C-Clamp produced. It's forcing screw has a square head designed to be turned with a wrench or 4 / 8 Point Socket due to high load capacity. This clamp meets or exceed US Federal Spec. GGG-C-406D.