Environment-proof, self-contained proximity sensor enclosed in a rugged stainless steel housing, designed to meet the requirements of aerospace, ordnance, marine, mass transit and high performance industrial equipment. Operation by the Hall-effect principle, which is used to detect magnetic fields passing in front of the sensing face. Once a target magnet is detected, a trigger signal is produced which is then passed through the output conditioning circuitry to give a high or low output, depending on the sensor application.