Used in the following models: 501, 651, 751, ER 152, ER 302, ER 202, ER 402, ER 252, 502, 652, 752, CB 497, CW 497, CB 647, CW 647, CB 747, CW 747, CH 401, 401, CH 501, 501, CH 651, 651, CH 751, 751, CH 402, 402, CH 502, 502, CH 652, 652, CH 752, 752, CB 495, CW 495, CB 645, CW 645, CB 745, CW 745, Lochinvar Parts, Pool Heater Parts, Copper Fin II 501-2071