Vixen Horns Loud 145dB Single Semi Truck Chrome Plated Train Air Horn 12V/24V VXH1164 This product requires an Onboard Air System Single trumpet, metal chrome plated air horn Terrifically loud 12V/24V Electric Air Valve (solenoid) with Compression Fitting 3/8 inch OD Nylon Plastic Hose (6 Feet)