Kleinn Air Horns 141 Compact Quad Air Horn - Chrome Four Air Horn Trumpets, 13-Inches, 11-Inches, 8-1/2 and 7-Inches Requires 150-PSI Onboard Air System (Not Included) All Metal Body With Chrome Plated Zinc Alloy Trumpets Vortex 4  12-Volt Electronic Air Horn Solenoid Included Up to 150.3-Decibel Output