Hella's Twin-Trumpet horn kit is a great upgrade for any vehicle. These trumpet horns look and sound like nothing else on the road. These horns guarantee the attention needed in critical situations. The twin trumpets are self contained, there is no compressor to mount so this is a great choice where there are space constraints. Sound level is 110Db, Frequency 500Hz high tone, 400Hz low tone, Draws 6 amps each trumpet. Kit includes one high and one low tone trumpet unit, relay, mounting hardware and instructions. Dimensions: 5.00 inch high x 4.30 inch wide x 3.2 inch diameter including mounting bracket