The 1/2” plug for hot tub plumbing has a spigot (SPG) end and is made by Dura Plastics designed to fit inside a coupling or plumbing part referenced as having 1/2” slip end. It does not fit inside a 1/2” flex or rigid pipe for pool or hot tub applications. In the pool and hot tub industry, plumbing dimensions are referenced as nominal and not actual; see the diagram below for the actual dimensions for this plug.
Details:
- Manufacturer P/N: 449-005
 - Type: Plug
 - End: 1/2" SPG (Actual 13/16")
 - Material: PVC
 - Max Temperature: 140F
 - Colour: White
 - Application: Pool and Hot tub plumbing