Flexibility of traffic control during and after business hours is offered by 4510 Series Deadlatches. A reverse turn of the key while bolt is held retracted retains the bolt, to allow two way traffic for hospitals, banks, and other buildings which require free entrance at certain times and exit only at other times. Interchangeable, without stile modification, with any MS1850A or MS1850S deadbolt of same backset and faceplate shape. (They do not, however, provide the same maximum security level as the MS Deadbolt.) Lock case is steel with corrosion-resistant plating. Available in four cylinder backsets, 7/8 In., 31/32 In., 1-1/8 In. or 1-1/2 In.. All metal latch bolt with hardened steel internal pins. Handing is reversible without special tools. All metal auxiliary bolt deadlocks latch bolt to prevent loiding or case-knife entry. Standard strike furnished is 4902-01 for flat jamb where door closes flush or nearly flush. Also available: radius strike for opposite stile in paired doors; longer strike (4901) to cover slot strike of MS lock; long lip strikes for centerhung doors. Turn key or operate handle to retract spring-loaded latch bolt. To hold bolt retracted, push it in and secure by reverse turn of key. Uses any standard mortise cylinder with MS cam. Individually boxed with strike and machine screws for mounting. Cylinders, paddle or handle available at extra cost. Satin Aluminum Clear Anodized