This Loud Train Sound Air Horn is entirely made of metal, Triple Chrome Plated to withstand all weather conditions. Comes with a 1.5 (6 liter) air tank, 150 PSI 12 volt heavy duty air compressor, air pressure gauge, pressure switch, mounting hardware, hose, fittings and instructions. Horn will produce a very loud 149 decibels, and surely will get anybody's attention around you. Great for SUV, truck, RV, pick-up, marine use and many more applications. Horn Size: 12-1/4" long x 13-3/4" wide x 4-1/2 high. Trumpet Sizes: 13-3/4", 11-1/2", 9", 7-1/2", 3-3/4" diameter each. Air Tank/Compressor size: 16" L x 11-1/2" H.