First, you need to cut the PVC pipe to your desired length of your knee cap. Then, I used a Saw-all to cut a vertical line down the pipe. Next, heat the pipe evenly with the hot air heat gun to soften the plastic. Then, use a 3 inch putty knife to pry apart the pipe and mould the pipe into a U shape. Always wear thick leather gloves during the operation or you will burn your hands!!