High Quality Heavy Duty F-Clamp ClipEngineering grade plastics Clamp with 45 # steel Fast regressive key can quickly adjust the holding distance Soft rubber clamps can effectively protect the object being clamped. Fast switching of positive and negative bidirectional clamping. The 4 inch F clip is too small and there is no hand screw. The positive and negative switching requires the use of a screwdriver. Size: Note: All dimensions data are manually measured and there will be errors.