Proximity switch with snap lock

A proximity switch (20, 20A) that snaps quickly and locks between first and second positions of movable electrical contacts (32). A magnet (42) moves a first shaft (26) toward a magnetic target (62) when the target is proximate a sensor end (43) of the switch housing (22). A spring (44) urges the first shaft (26) away from the sensor end. Movement of the first shaft causes a second spring (64) to urge a second shaft (28) in the direction of the first shaft. Next the second shaft is released (52) to move in the direction urged by the second spring. The switch may be adapted to a client cable pin configuration via an adapter plug (80) in the housing with a flexible interconnection circuit (82) folded in a chamber between the adapter plug and leads from fixed electrical contacts (38) of the switch.