A theft deterrent device includes first and second jaws pivotally connected to one another and pivotally movable between open and closed positions. The jaws form in the closed position an interior chamber and a through passage for receiving therethrough a portion of an article of merchandise. A lock slide is slidable within the interior chamber between locked and unlocked positions and lockable by a lock in the locked position to secure the first and second jaws together in the closed position. The lock slide includes lock hooks which lockably engage lock hooks of the second jaw. The lock slide includes locking and unlocking ledges which a resilient, magnetically attractable lock finger of the lock respectively engages in the locked and unlocked positions. An externally accessible thumb grip operatively engages the lock slide to move it between the locked and unlocked positions. An EAS tag is disposed within the device.