Two types of product families are available that indicate of the presence of air pressure in pneumatic systems. Several visual indicators for either panel or in line mounting provide the operator clear visual signals of system pressure for aid in machine operation and trouble shooting. Units are constructed of molded materials with clear high visibility lenses. Pressure switches (P/E switches) provide electrical contact outputs to electromechanical or electronic devices signaling the presence of air pressure. Two types are available with pressure adjustment capability. Units are made of molded materials and have several contact output ratings.