What is this called?

[tom8521]

I posted on here yesterday saying, I may have bought a shower that wouldn't fit my where my old one came out.

Today it arrived, and sure enough it didn't fit.

My new shower has hot and cold water pipe connections that are 3/4"
but my old shower water connections were only 1/2".

I'm wondering if such a thing exists to transform the connection from 3/4" into 1/2"

I saw this which looks like it might have 2 different sized ends.. what is the name of such a thing.. other than "nut"?

View media item 84305

 

[Newboy]

A reducing bush

 

[Agile]

Maybe you need to upsize the supply pipes from the source?