Wolo (842 Orient Express Plus Truck Train Horn - 12 Volt Designed smaller in size for the vehicle owner that wants a powerful train horn sound Made to fit into an engine compartment that has less available space The four trumpets are brass triple chrome plated to have a bright finish Built into the base of the trumpet is a 12 volt electric solenoid valve which is chrome plated Comes complete with a high-pressure on-board tank system consisting of a heavy duty compressor and a 5.5 liter extended air storage tank