Hot tub pump union gasket with ribbed O-ring on one side and flat on the other side.  This gasket is labeled and referred to as a 2-1/2" gasket which fits hot tub pump and heater unions referenced as 2-1/2". Made of a silicone based material for long life.

• Waterway P/N 711-6020
• Outside diameter 3-3/8"
• Inside diameter 2-1/2"
• Flat on one side, o-ring rib on other side