STPs are marketed primarily through petroleum equipment distributors. They are also sold directly to major oil companies. Petroleum equipment distributors sell various products, including STPs, to service station owners and operators, independent firms known as jobbers that operate service stations, and the building contractors who construct or service the stations. Suction pumps, which are used mostly in service stations outside the United States, are not an adequate substitute for STPs sold in the United States. Unlike STPs, suction pumps are located above ground in each dispenser.
Suction pumps draw the gasoline from the storage tank using a suctioning technique.
They operate by reducing pressure at the pump inlet and allow atmospheric pressure to push the gasoline from the tank into the pump where it is pushed through the hose and nozzle. In a suction pump system, each dispenser requires its own suction pump and separate piping from the dispenser to each storage tank, whereas STPs require only one main pipe with branches to each dispenser. Because of their superior performance and lower cost, STPs have virtually eliminated sales of suction pumps for gasoline service stations in the United States. For the vast majority of service stations in the United States, STPs are much more economical than suction pumps. The average size service station in the United States has about six dual-side dispensers and three underground storage tanks.