Pentair R172214 Lock Ring Replacement Pool/Spa Filter, Feeder and Leaf Traps Lock 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 pool and spa leaf trap models 179, 179-HDB, 179-C, 179C HDB Also compatible with Pentair Rainbow high capacity automatic chlorine/bromine pool and spa feeder models HC-3315, HC-3330, HC-3340 Also fits Pentair Predator II mini-cellular media cartridge filters