Bottom entry 1/2 inch BSP plastic float valve / ball-cock, for your WC / toilet cistern.
Adjustable length arm.
Flow restrictors for high and low pressure water supplies included.
Threaded ball mounting end has 5/16 inch British Standard Whitworth (BSW) thread - use standard 4-1/2 inch float.
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.