This is the BARB FITTING only.
It is the small piece that screws into the supply valve, houses the supply valve filter and connects with the supply hose.
This is #9 on the new system diagram.
Photos:
Updated May 2025 supply barb fitting
Supply barb fitting on Aug 2024 updated supply valve
Supply barb fitting on older style supply valve
System diagram
Supply valve updated 8/2024 to the brass fitting in 2nd image.
(Other parts sold separately, image for reference only)