Electric strikes replace the regular strike and come in both fail safe and fail secure models, with either regular or panic hardware. The spring-loaded keeper on the electric strike controls the latchbolt of the lock or panic hardware. When access is allowed, the keeper is freed and the latchbolt can be pulled through the keeper in order to open the door.
An electro-magnetic lock is electrified and controlled by a card reader, remote release or other access control device. A fail secure lockset is locked on the secure side when there is no power to the lock. When power is applied due to someone tapping a card on a reader or entering a keypad code, the magnet is powered off and the door is unlocked.