Generic Buna-N O-Ring [15-15/16" ID] [5/16" CS] (90-423-6115) leviton A return face cover is

A return face cover is useful because it helps finish the return opening neatly

or no longer controlling flow direction correctly

An eyeball inlet fitting like this is useful because it helps return water to the pool or spa while also allowing directional adjustment of the return flow

Full control system for compatible BP1500 spa applications

which many users prefer because it feels more active than a simple fixed jet

Generic Buna-N O-Ring [15-15/16" ID] [5/16" CS] (90-423-6115) leviton A return face cover isA Buna N O ring helps create a seal at a compatible large diameter circular connection, and this generic version is sized with a 15 15 16 inch inside diameter and a substantial 5 16 inch cross section using the 90 423 6115 reference. When a large profile O ring becomes worn, stretched, or compressed, the assembly can lose the sealing support it should maintain around the full circumference. The heavier 5 16 inch cross section gives this O ring