Ardillion presents one of the best selling item: Universal Dual Tone Universal Claxon (set of 2 sirens) Provide loud LEGAL sound E1 marked Brand New Twin Tone Horn Set with relay Great replacement kit or additional horn upgrade Dual Tone Includes Mounting Material Instalation Diagram in the package 12V supply needed 1x 60 dB Low Harmonic Tone 12V 410Hz 1x 60 dB High Harmonic Tone 12V 510Hz No air supply required Relay included Suitable for CAR TRUCK TRAILER LORRY VAN CHASSIS BUS PICKUP SUV QUAD CARAVAN CAMPER MOTORHOME HORSEBOX FLATCAR FLATBED DRAY CART BOX ATV