4550 MS® Deadlock Lever

Description: The 4550 MS Deadlock Lever easily unlocks an MS®Deadlock with approximately three pounds of downward force. The spring-loaded lever relocks with an upward motion.

Function: Easy unlocking of any MS Deadlock by approximately 3 pounds downward force on a 3” lever. Lever is spring loaded to horizontal, relocks with upward motion. Indicator signals lock status. Can be installed in place of existing key cylinder or cylinder type thumbturn on inside of door. 4550 Deadlock Lever not compatible with 7/8” backset locks.

Operation: Turn lever downward 90° to unlock. When released, lever returns to horizontal. Turn lever upward 90° to relock. Key operation from outside is not affected. Clutching action prevents damage to internal components.


Housing: Aluminum casting is 1-3/8” wide x 7-1/2” long x 1” deep.

Lever: 3” long aluminum with end-return design offers comfortable grip to lock or unlock.

Indicator: Words “LOCKED” in red letters or “OPEN” in black letters appear on white background when lock is thrown or retracted. Indicator is driven by lock bolt itself.

Stop Clearance: Lever housing projects 11/16” forward of cylinder backset centerline. Depending on height of door stop and width of door/jamb gap, it may be necessary to modify the stop to clear the housing. For fin type stops, this is easily accomplished. Hollow stops may preclude use of lever.

Compatible Deadlocks: Any MS® pivoted bolt deadlock including “Schoolhouse” versions can be fitted with the 4550 including MS1850S, MS1950, MS1837, etc. Derivative units such as 1870, 1870HM, or 1877 flushbolts (bolt into threshold) are also operable by the 4550 lever. Not compatible with MS+1890 Deadlock/Latch or with 7/8” backset locks.

Options: Available in three finishes to match anodized aluminum finishes. Can be ordered for left or right hand door, but is easily reconfigured in the field to accommodate either door swing.

Standard Package: Individually boxed with installation instructions, mounting screws, and drive pins for both single point and threshold bolt-equipped locks. Shipping weight: 1 lb.


Compatible Products – This product is compatible with the following products:

Deadlocks Flushbolts

 MS1837, MS1850S, MS1850SN, MS1861, MS1950.

Not compatible with 7/8” backset .

1870 Series Cylinder-Operated Flushbolts.

1877 Cylinder-Operated Flushbolts.