15mm compression x 1/2 inch BSP elbow service valve.
Turn off / on with screwdriver.
Complete with sealing washer.
Just the right size for a toilet cistern float valve or kitchen sink / bathroom basin taps.
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.