Davis Quick Fist Rubber Clamp 540, Super Quick Fist Clamp 544 Bundle (2 Items). 540 Quick First, a one piece rubber clamp that mounts easily to keep tools and equipment firmly in place. For off-road trucks, boats, military equipment, ATVs, vehicles. 544 Super Quick Fist for holding fire extinguishers, oxygen cylinders, CO2 tanks, and other equipment. Mounts easily with three #10 (5 mm) screws.