Stebel Horn (Nautilus Twin Air); Universal Made by the world-famous Stebel of Italy, this quality air horn kicks out 139dB of sound! For comparison, a shotgun blast is about 140 dB.This will mount to any scooter, motorcycle, car, truck, or boat. All you need is 12v power and a good mounting point! Mounting bolt and relay included. Fits: UniversalBrand: StebelSize: 5in x 4.25in x 2.75in