Provide accessible interior operation of compatible Adams Rite MS® deadlocks with the Adams Rite 4550 MS® Deadlock Lever Handle.

The 4550 installs in place of an interior key cylinder or cylinder-style thumbturn and allows the user to unlock a compatible MS® deadlock with approximately 3 lbs. of downward force on the lever.

A built-in LOCKED / OPEN indicator provides a clear visual indication of deadbolt position, making the 4550 an excellent choice for commercial storefront, institutional, and accessibility-focused openings.

Key Features

• Genuine Adams Rite / ASSA ABLOY

• Model 4550

• MS® Deadlock Lever Handle

• Interior deadlock operator

• Approximately 3 lbs. operating force

• 3" aluminum lever

• End-return lever design

• Spring-loaded return to horizontal

• 90° downward movement unlocks

• 90° upward movement locks

• Built-in LOCKED / OPEN indicator

• Indicator is driven directly by lock-bolt position

• Internal clutching action helps prevent damage

• Replaces compatible interior cylinder or thumbturn

• Exterior key operation remains unaffected

• Left- and right-hand configurations

• Handing can be changed in the field

• Multiple architectural finishes

• Compatible with selected MS® deadlocks and flushbolts

Easy Lever Operation

The 4550 provides simple interior operation of the compatible deadlock.

Unlock

Rotate the lever:

90° Downward

This retracts the deadbolt.

When released, the lever automatically returns to the horizontal position.

Lock

Rotate the lever:

90° Upward

This projects the deadbolt and secures the opening.

Low Operating Force

The 4550 requires approximately:

3 lbs. of downward force

to unlock a compatible MS® deadlock.

This makes the lever a convenient alternative to a conventional thumbturn or interior key cylinder.

LOCKED / OPEN Indicator

The 4550 includes an integral visual lock-status indicator.

When Locked

The indicator displays:

LOCKED

in red lettering.

When Unlocked

The indicator displays:

OPEN

in green lettering.

Because the indicator is mechanically driven by the deadbolt itself, it reflects the actual bolt position.

Compatible Adams Rite Deadlocks

The 4550 is compatible with applicable configurations of:

• MS1850S Series

• MS1850SN Series

• MS1950 Series

• Compatible MS® Schoolhouse versions

Compatible Flushbolts

The 4550 can also operate compatible:

• 1870 Series Cylinder-Operated Flushbolts

• 1870HM Series Cylinder-Operated Flushbolts

Important Backset Restriction

Not Compatible with 7/8" Backset Locks

The Adams Rite 4550 is:

Not compatible with 7/8" backset MS® locks.

Always verify the lock backset before ordering.

Not Compatible With

The 4550 is not designed for:

• MS+1890 Deadlock/Deadlatch

• 2190 Dual Force® Interconnected Deadbolt/Deadlatch

• 2290 Dual Force® Interconnected Deadbolt/Deadlatch

• MS1847

• 5017

• Standard Adams Rite deadlatches such as 4510 or 4900

Use the appropriate paddle, lever, or turn operator for those products.

Left or Right Hand

The 4550 is available for:

• Left Hand / Left Hand Reverse

• Right Hand / Right Hand Reverse

The trim is ordered by handing but can be reconfigured in the field from right to left or left to right if required.

Lever

Material: Aluminum

Length: Approximately 3"

The end-return design provides a comfortable grip while helping minimize snag points.

Housing

The housing is constructed from:

Cast Aluminum

Approximate Dimensions

Width: 1-3/8"
Height: 7-1/2"
Depth: 1"

Door Stop Clearance

Important Installation Note

The 4550 housing projects approximately:

11/16" forward of the cylinder backset centerline

Depending on the:

• Door stop

• Frame profile

• Door-to-jamb gap

• Existing opening geometry

the stop may require modification for proper clearance.

Fin-style stops may often be modified, while some hollow stops may prevent use of the 4550.

Clutching Mechanism

The 4550 includes an internal clutching mechanism that helps protect the lock and trim if excessive force is applied to the lever.

This is particularly useful in high-traffic commercial applications.

Exterior Key Operation

Installing the 4550 on the interior side does not interfere with normal exterior key operation.

The exterior mortise cylinder can continue to operate the MS® deadlock normally.

Common Applications

Ideal for:

• Aluminum storefront doors

• Narrow-stile commercial doors

• Hollow metal doors using compatible MS1850SN locks

• Retail entrances

• Schools

• Healthcare facilities

• Government buildings

• Office buildings

• Institutional facilities

• Commercial entrances

• Interior deadbolt-release applications

Product Specifications

Brand: Adams Rite
Series: 4550
Product Type: MS® Deadlock Lever Handle
Installation: Interior Side
Lever Length: Approx. 3"
Operating Force: Approx. 3 lbs.
Unlock Operation: 90° Downward
Lock Operation: 90° Upward
Lever Return: Spring Loaded
Indicator: LOCKED / OPEN
Housing Material: Cast Aluminum
Housing Width: 1-3/8"
Housing Height: 7-1/2"
Housing Depth: 1"
Housing Projection: Approx. 11/16" Forward of Cylinder Centerline
Handing: Left or Right
Field Rehandable: Yes
7/8" Backset Compatible: No
Approximate Shipping Weight: 3 lbs.

What's Included

Standard package includes:

• Adams Rite 4550 Lever Assembly

• LOCKED / OPEN Indicator

• Mounting hardware

• Drive pins for compatible single-point deadlocks

• Drive pins for compatible threshold-bolt applications

Not Included Unless Specifically Stated

• MS® deadlock

• Mortise cylinder

• Exterior cylinder

• Flushbolt

• Strike

• Door

• Frame

Important Ordering Information

Before ordering, verify:

• Compatible MS® deadlock or flushbolt

• Lock backset

• Left- or right-hand configuration

• Required finish

• Door-stop clearance

• Existing interior cylinder / thumbturn preparation

Important

The 4550 is lever trim only.

A compatible Adams Rite MS® deadlock or flushbolt is required and sold separately.