• Tweco® Roto-Work 500 A Ground C Clamp with 1 3/8" jaw depth and 2 1/2" jaw opening perfectly works in conjunction with Tweco® Roto-Ground device. Clamp with 1/2" cap screw is constructed from copper alloy and can be used for other high amperage Ground applications. Clamp affixes or moves quickly from one rotating weldment or fixture to the other without removing device from it. Clamp saves welding down time. Roto-Ground device shaft, screws into the tapped back of the clamp. It offers efficient operation with large tightening screws as well as ample contact surface area.