Abstract: A switch plunger is covered at its exposed end with a serrated cap which is ratchetable over the end of the plunger. The plunger is axially slidable within a housing upon which is mounted a selectively operable locking pin. The locking pin may be actuated during installation of the switch so as to fix the relative position of the plunger within the housing during installation. This initial setting of the plunger within the housing also aligns a pair of electrical contacts mounted on the plunger with cooperating circuitry mounted within the housing. The switch is initially installed and calibrated simply by engaging the lock pin with the plunger and inserting the switch within an aperature formed in a cover or housing and abutting the cap with a switch actuator.