21" Sta-Rite System 3 S7S50 Filter Tank O-Ring Rebuild Kit 24850-0008 Sta-rite System 3 S7S50, S7M120 Cartridge Filter O-ring Kit Includes: 5, 23, 14, 15, 11, 12, as shown in diagram Quality replacement parts by TORK Distributors This fits the 21" tank only, NOT the 25" Order will arrive with TORK packaging, anything else is not from this ad or brand