This tool tip made my co-worker and our customer so happy that he made one and wrote my name on it. Some may know this trick, but it’s always a good share for others who may not know. It works on the bonnet nut for Delta single handle shower valves. Often the bonnet nut can become stuck. Just tighten the 2” fernco on it with a PC of pipe on the other side, and off it comes allowing for cartridge replacement. This avoids costly valve replacement when not needed.