Proportion-Air, Inc. is a manufacturer of electronic air pressure regulators and air flow control valves. Proportion-Air, Inc. was founded in 1985 by corporate president Daniel E. Cook to capitalize on the sales and marketing prospects of the unique invention of an electronic air pressure regulator.

This air pressure device was designed to accept a variety of electronic analog and digital signals in order to control pneumatic pressures with extreme accuracy while negating the effects of vibration, mounting position or environmental concerns.