WORKPRO 2PCS 6" Mini Light-Duty Bar Clamps Set One-Handed Clamp/Spreader F Clamp

Clamp & Spreader: The screw-release button design allows the f clamp to be a spreader. Just release the button by a screw and then reverse it before fastening it, you will get the spreader you need. The 6" clamp can be set to a spreader with sizes up to 7-7/8".