Trap extension 1-1/4 inch male x female BSP x 1 inch long.
Extends your wash hand basin waste by 1 inch.
1¼″ BSP thread - Standard bathroom wash hand basin waste size.
One end male, the other female.
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.