Everyone has experienced the need to fasten their seat belts; and because of the safety aspect, laws have been passed making it mandatory to ‘buckle up’. Identifying a reliable technology that could be used to indicate the closure and opening of a seat belt aboard an aircraft has been a difficult challenge until Proximity Sensors were considered. Aboard an aircraft, several times a day, different passengers will make the aircraft seat their residence. Some of these people are careful and conscience and some are not as careful, the net result to the seat belt is that it can be slammed around, spilled upon, splattered with food, used as toys by children, etc. etc. The hermetically sealed Proximity Switch is perfectly suited to withstand the above abuses and still perform its switching function.