POWERHOUSE ROOF MOUNT DUAL TRUMPET AIR HORNS are chrome plated metal trumpets with weather protection covers that easily attach to front of trumpets. For roof mounting on Trucks, RV’S, Vans, Etc. The Powerhouse offers extra loud big truck sound, with a heavy-duty 12 volt compressor that is totally maintenance free. Kit includes Wolo’s new flexible inlet hose with brass fittings, relay, hose, and mounting hardware. 120 Decibels 390/435 Hz., Longest Trumpet 13-1/2 in.