Key Swith Exit Device

A key switch (sometimes called a lock switch to distinguish it from a keyswitch) is a switch that can be activated only by the use of a key. They are usually used in situations where
access needs to be restricted to the switch’s functions.[citation needed] Key switches are available as components with solder connections, and are available with a variety of ampere ratings.
They may use tubular or other specially-shaped keys for extra security. Key switches have been used for a variety of purposes, up to and including the launch of nuclear missiles. In less
secure applications such as corridor and restroom lighting controls in public buildings, tamper-resistant switches with a simpler key mechanism may be used instead.