A pump-assist oil drain lets you hook up a suction hose directly to a full oil drain and transfer oil from the drain to the waste oil tank. Shop air usually runs the diaphragm suction pump.
Pump-assist oil drains can vary in size from 8 gallons for a smaller shop with a couple of bays to around 30 gallons for a high-volume operation with multiple bays. Shops already using a diaphragm pump can benefit the most from using a pump-assist oil drain to empty used oil, and then get back to work quickly.