Triple-Fuel Yamaha Inverter 3,500 Watt Boost - On a 20 lb propane tank, this set will run for 24 hours. Then, switch over to gasoline, and it will run for another 21 hours on a full tank of gasoline. That's 45 hours of clean, efficient and quiet electrical power! This unit will operate on LP Gas, Natural Gas and Gasoline right out of the box! No mechanical alterations are necessary - simply change your fuel source! Features include Yamaha 4 Stroke OHV engine, frame mounted control panel, oil warning system, USFS approved spark arrestor, 12 VDC output w/ battery charging cables, Economy Control (automatically changes the engine speed to match power demand), large super quiet muffler, frame mounted 3.4 gallon fuel tank, sound level of 51 dB(A), electric starting and integrated wheel system. DOES NOT INCLUDE LP HOSE & TANK.