PHOTO 1: Cut a 1/4 inch hole in the inner tube. PHOTO 2: Take a 1/2 inch pipe coupler and cut off it's lower half. PHOTO 3: Spread a good amount of rubber-sealing compound on the small ridge of the coupler. Insert into the inner tube's hole. PHOTO 4: Put some rubber-sealer on your finger and coat the outside area. PHOTO 6: The portable solar water heater can easily be emptied, rolled up, and tucked into a backpack or satchel.