This Surrey flange improves water quality by reducing air content, often solving problems of airlocks in shower pumps and power showers.
1 inch BSP male connection into cylinder.
1 inch BSP female connection at top of flange.
3/4 inch BSP female shower connection on the side.
BSP (British Standard Pipe Thread) sizes don’t match up with what you would measure using a ruler. Have a look at the BSPT link at the bottom of this page for more information about how plumbing threads are measured.