An electric door strike is basically a strike plate on a door that operates electronically to open and close the door.
The electric door strike is used in secure places where people enter access codes or uses a card to access the secured location electronically.
The electric door strike uses electric current to unlock and unlatch the door for it to open but on the other side of the electric strike it's possible to still open the door for emergencies using a key or just by turning the doorknob in case the electric current is turned off or a power failure happens.
Here's a picture of an electric door strike.
