Exit Buttons are required by code, for possible malfunction of motion exit sensor. The exit button is mounted next to door and momentarily pressing the button releases the door for the set amount of time required by code. There are many different styles but they all have the same function. The buttons are douoble pole, meaning they have 2 sets of contacts. One set is used to directly break lock power and the second is used to send a signal to the access control system in orded to shunt varius alarms while entering the door. In most cases the button os mountd in a metal enclosure mounted on the door frame. There is a maximum distance the button can be mounted from the door.