I bought two of these to secure my 10lb CO2 tank to the back of my 2012 Toyota Tundra. I pretensioned the straps around the tank on my workbench before installing it on the truck. This greatly simplified installation around the tank. I installed the clamps with (3) #10 1-1/2 self-tapping sheet metal screws on each belt; two outer holes with 3/16" washers underneath and a standard washer under the center bolt. This added an incredibly safe and secure mount to my tank. Without the use of thumb washers or some sort of large cap screw these would be a fairly unpredictable mount and would not hold up when attempting to secure them around the tank.