Jenvey Air Horn Tapered 51mm x 90mmJenvey lightweight Aluminium Spun Air Horn with a 51 mm bore, measures 90 mm long with a 4. 5 degree taper at outlet to match standard throttle body taper with 5 mm holes in the flange. The inlet diameter is 100 mm so trimming may be required where bore spacing is less. Designed to suit Jenvey Individual Throttle Bodies. Specifications Bore 51 mm Length 90 mm Flange Hole 5 mm Tapered Outlet 4. 5 Material Aluminium Approx. Weight 0. 1 kg