C100500 Cartridge is used on all Sloan Flushmate Systems EXCEPT the 200 Series. Fits tanks 500, 501, 501A, 501B, 503, 504, F31A, F3A, F3AR, F3C, F3CR, F3CC, FCE, F3ER, F31, F3G, F3G2, F3L, F3LR, F3, F3R, F3M, F3MP, F3MR, F3O, F3U, F3UR, F3Z, F32, F3K, F3KR, F3G4, F3G3, F3GR, F3K1, F3K2, F4A, F4AP, F4P, F4L, F4LR, F4N, F4B, F4C, F4K, F4KR, F4MP, F4J, F4M, F4V1, F4V2, F4V. Fits all American Standard, Briggs, Caroma, Ceralux, Eljer, Gerber, HCG Hocheng Corp, Kohler, Lamosa, Mancesa, Mansfield, Niagara, Orion, Peerless, St. Thomas, Vitra, Vitromex, Vortens, Western Pottery, Xinqi