This is a plug used to plug off a 3/4" port on Waterway Smart Plumb Style Manifolds Only..
We offer many different plugs based on the brand of manifold.
Barb Adapter 3/4" Barb x 1/2" Spigot , The Glue Side glues inside a 1/2" Fitting which would measure 3/4" and a 3/4" ID tube would be glued over the barb.
This part is a Bleeder Barb that is 3/8" barb x 1/4" Threaded MPT fitting fits Wet End Face Bleeder Plug Holes to attach a Bleeder Line it fits Waterway Executive 48 & 56 Frame Parts...