|Brass ON / OFF Valve for shower valve replacement. This part is designed for replacement in suitable 3 dial thermostatic shower valves. This part is from the middle of the three dials (water on / off).
The main barrel is 17mm in diameter and overall length 77mm.
1/2" Replacement Brass Ceramic Disc Tap Valve Cartridge Turn Quarter
AquaLusso have produced this useful video on replacing the ON OFF Valve: