Roof-mounted dual horn features 15 inches and 13 inches trumpets to create a deafening blast of over-the-road fury. Note: This model 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 for operation. Dual truck horn Chrome-plated, spun copper Maximum output 153.5 decibel 14.75 inches overall length 7 inches overall width MODEL NO - 401