Automatically deadlocked when door is in the closed position. Particularly suitable for glass panel doors. Reverse bolt pattern available for outward opening doors. Latchbolt is withdrawn by handle from inside and key outside. Handle can be deadlocked by key prior to closing the door and entry can always be gained by key from outside. Bolt can be held back by slide button or locked in either the withdrawn or extended position by a turn of the key in the middle.