Cherry MP201701 is encapsulated reed switch sensor with SPST contacts that can be activated by a magnet (not included). These are found in door position & interlock alarm systems, pedal switch etc. Operate/release distance 0.15" to 0.5". Rated 175VAC/VDC @ 0.5Amp. Size 1" long x 0.243" dia. with 12" long insulated leads. New - Retails for $5.50.