If space is a problem (and it often is under the bonnet), then RING has the answer with the new Compact Twin-Tone Air Horn.
The RAH900 has an integral 12V compressor and a Titanic 114dB output. Measuring only 5” X 4” X 3” it will fit just about anywhere under the bonnet or on a Motorcycle. The Air Horn is mounted with a single bolt and comes with a 12V relay. Part No: RAH900.
Ring is distributed by Strongline Autoparts Ltd.