Dual Truck Horn; Chrome-plated, spun copper; Maximum output 153.5 dB; 14.75" overall length; 7" overall width Our Roof-Mounted Dual horn features 15? and 13? trumpets to create a deafening blast of over-the-road fury. Note : Model 401 does not include a valve and requires the use of a solenoid valve or hand pull valve as well as a Roof Mount Air Horn Fittings Kit (p/n 330) for operation. Click here to download the warranty for this product