Help Identifying Connector

[Nathan Oursler]

Hello, homeowner not plumber. I've been trying to figure out what to call a specific part of the fixture, the connection from the supply to the actual faucet fixture in a bathtub. Where the transition occurs from 12in supply to 1in nut which screws around the mail end of the fixture. Pictures attached for reference. I'm having a real time of trying to find the piece at a hardware or my local plumbing store and haven't been able to name it specifically enough for an internet search to return what I'm looking for. Any help is appreciated. Thanks!

^The Fixture in question^ ^the specific part I'm looking for^

 

[SHEPLMBR]

It may be proprietary to that brand. Call the manufacturer. It's called a flange.

 

[Twowaxhack]

It’s called a tub union and each brand has their own cut so they’re not interchangeable.