The Schrader valve (also called American valve) is a brand of pneumatic tire valve used on virtually every motor vehicle in the world today. The Schrader company, for which it was named, was founded in 1844 by August Schrader. The original Schrader valve design was patented in the United States in 1893.
The Schrader valve consists of a valve stem into which a valve core is threaded, and is used on virtually all automobile tires and most wider rimmed bicycle tires. The valve core is a poppet valve assisted by a spring.
In addition to tube and tubeless tires, Schrader valves of varying diameters are used on many refrigeration and air conditioning systems to allow servicing, including recharging with refrigerant; by plumbers conducting leak-down pressure tests on pipe installations; as a bleeding and test port on the fuel rail of some fuel injected engines; and in the buoyancy compensator (BC) inflators of SCUBA systems (the inflation button pushes down on the valve, allowing pressurized gas to flow into the BC). Schrader valves are also widely used in high-pressure hydraulic systems on aircraft.[citation needed] Many domestic fire extinguishers use an internal valve identical to a Schrader valve, but with a lever on top to enable quick release of the pressurised content.