The ANSI size MS1850SN-45X Series MS Deadlock utilizes a stainless steel hook bolt activated by a pivot mechanism to provide maximum security for hollow metal or wood doors. The ANSI size MS1850SN-45X Series MS Deadlock provides maximum security and ease of installation for hollow metal or wood sliding doors. Its standard 1-1/2" (38.1 mm) backset dimension provides adequate clearance for the deep jamb "pocket" of many commercial and industrial entrances. The locking mechanism is identical to the widely used MS1850S Series MS Deadlock, except that the massive laminated bolt is provided in a hook shape to resist the parting motion of sliding door and jamb. The over-center maximum security (MS) locking action assures that forced entry attempts to pry the door in any direction, up, down, or sideways will be defeated. Also useful for swinging doors closing against jambs too shallow for the 1-3/8" (34.9 mm) throw of the MS1850SN Series MS Deadlock. 360 degree turn of key or thumbturn projects or retracts the counterbalanced bolt. Key can be removed only when bolt is in a positively locked or unlocked position. Lock accepts any standard 1" (25.4 mm) length, 1-5/32" (29.4 mm) diameter mortise cylinder with MS cam such as the 4036 mortise cylinder or thumbturn such as the 4066 thumbturn, available separately. Lock accepts cylinder from either or both sides.