This Strike is 12vdc, Fail Secure (stays locked if loss of power). Your installer cuts this into the door jam, and it works with your current key locking, spring latch lock, and door closer. Now your desk person just pushes the button, and "click", the customer pulls the door opened. Then after entry, the door closer returns the door to the closed position, and the spring latch enters the special strike again, which in now locked.

Popular in doctor offices.
Pawn Shops.
Jewelry stores.
Quick food stores, and gas stations where there is need for extra security after dark.
All offices, and business that want to use card entry to keep a time of entry for which person.

Additional parts need for the installer, 2 conductor wire, a electronic button, and a plug in power supply.