Rheem UV12992 Heat Trap Nipples with 3/4-Inch NPT and 3-Inch Length, 2-Pack Nipples - heat trap - (3/4 in NPT x 3 in long) - pack of 2 Material: zinc plated steel/polypropylene liner, heat trap Type: flapper, thread size NPT (in.): 3/4, length (in.): 3 Lengthens life of water heater Set of 2