Fuel transfer pumps come in different types, sizes and flows. The most popular fuel transfer pumps are portable 12-volt or 115-volt fuel pumps and fuel pump/meter combinations for standard 2-inch tank burst threads. These fuel transfer pumps require the use of suction tubing that is cut off near the bottom of the tank and bolted to the pump inlet at the bottom of the pump. These fuel transfer pumps typically include 3/4 "or 1" delivery hoses and fuel nozzles, refueling trucks, tractors, construction machinery, and many other engine-driven engines. Another type of fuel transfer pump is a centrifugal pump, which is made of a fuel compatible material, including pump seals. These pumps can be self-priming or linear centrifugation as needed. Some gear pumps are also used to transport fuel, especially diesel, fuel oil and lubricants.