This brass valve is designed to control maximum rpm fuel flow curves by maintaining the air to fuel ratio required for good power throughout the whole rpm range. It is used mainly on large cubic inch engines that operate above 6000rpm, it consists of a body, cap, poppet, .042 spring, shims, and seal. The body is marked with the letter “C” and an arrow. When the valve is installed, the arrow should point toward the fuel tank. The valve is preset to open and relieve fuel when pressure is obtained, usually beginning around 6500rpm, and continues to open as rpm increases. The High Speed Cut-Off Valve can also be used as a simple pressure check or check valve for additional nozzles. It can be used to tailor a very rich bottom end fuel supply and a leaner top end curve. This valve can control the maximum pressure the engine will receive, conserving fuel for longer races.