Pentair R172224X Black Drain and Vent Valve Replacement Pool/Spa Filter and Feeder Drain and vent valve replacement Fits Pentair Dynamic series I, II RTL/RCF and III RTL/RCF inline pool/spa cartridge filter models RDC-25, RDC-25S, RDC-50, RDC-50S Also Pentair Rainbow high capacity automatic chlorine/bromine pool and spa feeder models HC-3315, HC-3330, HC-3340 Also compatible with Pentair Predator II mini-cellular media pool/spa cartridge filters and Dynamic RCF-RTL series cartridge filter chlorine/bromine dispensers Measures-8/9-inch length by 22/25-inch height by 3/4-inch width