Description

The Waterway 805-0145 is the o-ring for the 2 inch tail piece. It measures 2-5/8 inches inside diameter and 2-13/16 inches outside diameter.

Where it sits

The tail piece is the fitting that the union nut pulls up against, and this o-ring is the seal at that face. It is a small part carrying the entire joint. When it flattens with age, takes a nick from grit, or gets pinched during reassembly, the union weeps and no amount of extra torque on the nut stops it.

Check the size

Union o-rings in adjacent sizes look almost identical in the hand. Measure the old one across the inside and the outside and compare it against 2-5/8 inches and 2-13/16 inches before ordering. If a union is being opened anyway for pump or filter work, renewing the o-ring while it is apart is cheap insurance.