Boost control is the principle of controlling the boost level produced in the intake manifold of a turbocharged or supercharged engine by affecting the air pressure delivered to the pneumatic and mechanical wastegate actuator. Boost controllers can be as simple as a manual boost controller which can be easily fabricated oneself. One may also be included as part of the engine management computer in a factory turbocharged car, or an aftermarket electronic boost controller such as those made by Apex-i or Greddy.