"Brev Orlandi" style fuel tap made by OMG/PAIOLI - specifically fits a bevel drive 450 Ducati single and many others. M12 x 1.5 pitch [threads into tank] as used on 450 but will fit early 900SS, GTS, GT etc and other Italian motorcycles. The outlet is pointing straight down as you see. This is rebuildable and nicely made. Ian Falloon states the last of the GTS 900 came without crossover and where this style tap too.