The Pentair 192320 O-Ring Bulkhead Replacement Filter is an essential component for keeping HVAC systems running efficiently and long-term. This O-ring measures 3" by 3" by 0.25 "and is composed of sturdy rubber. It also has a sleek black color. It provides a tight and waterproof seal by replacing bulkhead fittings in HVAC systems. It assists in preventing leaks of air, water, or othe... https://www.usapoolshop.com/192320-pentair-o-ring-bulkhead-replacement-filter