Hayward S311SX Top Elbow Assy w/Diffuser (SX311CD1FWS) airbuttons A union like this is

A union like this is useful because it allows the connection to be disconnected for service later while still supporting a clean

Including the tube

Reference part number K11 when matching to your existing component

This replacement has practical value because it includes the screw

It is a practical maintenance accessory when verifying ozone-system activity is part of keeping service work accurate and efficient

Hayward S311SX Top Elbow Assy w/Diffuser (SX311CD1FWS) airbuttons A union like this isThe top elbow and diffuser assembly helps guide incoming water into the sand filter tank so it can spread across the media bed instead of channeling in one concentrated area. This Hayward replacement assembly is designed for compatible S311SX sand filters. A cracked elbow, missing diffuser, or worn internal connection can reduce filtration quality and put stress on other components. Replacing the assembly helps preserve proper flow distribution and