GearWrench 2189D 3/16”, 1/4”, 5/16” and 3/8” Tubing Bending Pliers GearWrench 2189D 3/16”, 1/4”, 5/16” and 3/8” Tubing Bending Pliers feature roller adapters are included for each tubing size, place tubing between the adapter and studs and squeeze the handles to bend, can bend 3/16”, 1/4”, 5/16” and 3/8” copper and steel tubing.