Aladdin O-500 O-Ring Replacement for Hayward DEX2400Z3A Air Relief Valve Stem O-ring replacement Fits Hayward Pro Series high rate sand filter models S210SV, S244SV Also fits Super Star-Clear cartridge filter models C2000, C3000, C4000, C5000 Compatible with Micro-Clear vertical grid D E filter This product weighs 2-pound