Hayward Pro Series Air Relief Knob O-ring 13/16 in. OD, SX200Z5
SX200Z5 O-ring for Pro-Series and Pro-Series Plus side mount side filters, Dome Air Relief Knob O-ring. Also used on Hayward S200/S240 sand filters as the Air bleed knob o-ring. Mates with Manual Air Relief Cap, part number SX200G, sold separately.