The Oil Extractor is designed for oil changes especially on big trucks and fleet equipment. It uses compressed air (shop air not included) at about 4 cfm to create a vacuum that sucks the oil out of the truck and into the 20 gal tank... you can change the oil when the engine is hot. Wheel this hand truck tank to the waste oil tank and empty by switching to the out position. It then pressurizes the tank forcing the oil out. Check out our website at www.clarksmfg.com for more details. FREE SHIPPING to the lower 48 states.