Pentair R172223 Housing O-Ring Replacement Pool/Spa Filter and Leaf Traps Housing o-ring replacement Fits Pentair Dynamic series I, II RTL/RCF, III RTL/RCF and V inline pool/spa cartridge filter models RDC-25, RDC-25S, RDC-50, RDC-50S, DSC 75, DSC 100 Also fits Pentair Dynamic RCF-RTL series cartridge filter chlorine/bromine dispensers Also compatible with Pentair Predator II mini-cellular media pool and spa cartridge filters Also fits Pentair pool and spa leaf trap models 179, 179-HDB, 179-C, 179C HDB, 186-A, 186-B, 186-C, 186-D