The MS1850S Series MS® Deadlock utilizes a laminated stainless steel bolt to provide maximum security for a single leaf narrow stile aluminum door. The MS1850S-X5X Series MS® Deadlock utilizes a laminated stainless steel hookbolt to provide maximum security for a sliding narrow stile aluminum door. Both are activated by a pivot mechanism. Function: A huge bolt of laminated stainless steel, nearly 3" long, activated by an uncomplicated pivot mechanism, has made the basic MS1850S Series MS® Deadlock the standard of the narrow stile aluminum door industry. The length of this bolt provides maximum security for a single leaf door, even a very tall and flexible one or an installation where the gap between the door and jamb is greater than it should be. The MS1850S-X5X Series MS® Deadlock answers the security need of sliding narrow stile aluminum doors in commercial, industrial, and institutional buildings. The locking mechanism is identical to the 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. Operation: 360° 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 4066Thumbturn, available separately. Lock accepts cylinder from either or both sides. This listing: part 1850S-320-628, in 628 Clear/Aluminum Anodized finish.