Product Description
5575NL-F-US4 Von Duprin 5575 Series with 550DT Night Latch Fire Rated Mortise Lock Device in Satin Brass
The Von Duprin 5575NL-F-US4 is a narrow stile mortise lock exit device that combines the 55 Series crossbar with a heavy-duty mortise lock body for maximum latch strength. Night Latch — outside lever locks and unlocks by key, inside always free for egress. When locked, key is required for re-entry from outside. Ships less cylinder — order a mortise cylinder separately to match your existing keyway.
The 5575 pairs the traditional crossbar activation with mortise-grade latching — a step up from rim devices when the door sees heavy traffic or requires the security of a mortise lockset. Requires full mortise pocket prep. This is a handed device — verify RHR or RHR before ordering. UL listed for fire exit hardware — no mechanical dogging on fire-rated models. ANSI/BHMA A156.3 Grade 1 certified.
Pro-Tip from Our Locksmiths: The 5575 pairs the 55 Series crossbar with a heavy-duty mortise lock body. That means you get mortise-grade latch strength plus the wide "strike zone" of the crossbar. Spec this when the door sees serious traffic — think hospital corridors or courthouse entries with narrow stile glass doors.
| Specifications | |
|---|---|
| Part Number | 5575NL-F-US4 |
| Function | NL - Night Latch |
| Grade | ANSI/BHMA A156.3 Grade 1 |
| Minimum Stile Width | 1-3/4" (44mm) |
| Door Material | Aluminum, Glass, Hollow Metal |
| Outside Trim | Included |
| Warranty | 5-Year Mechanical |
- Narrow stile crossbar design — fits door stiles as narrow as 1-3/4"
- Mortise lock body provides superior latch strength vs. rim devices
- UL listed for fire exit hardware — no mechanical dogging per code
- Handed device — factory-set for RHR or RHR
- Satin Brass (US4/606) finish
Works With: Add outside trim separately: 550DT Dummy Pull, 555NL Night Latch Pull, or 379L Lever Trim. The 55 Series uses dedicated narrow stile trim — standard 99 or 33A trim will NOT fit. Cover plate 589 required for wood door installations. For rim-mount option, see the 55 Series Rim. For concealed top-and-bottom latching, see the 5547 CVR.
Authorized Von Duprin Dealer — Lock Depot ships all Von Duprin products brand new in factory-sealed packaging with the complete manufacturer warranty. Same day shipping available on most orders. Questions? Contact us for free expert support.
Image shown is representative of the product line. Actual finish, trim, and configuration may vary by SKU.
Handing: Right Hand Reverse (RHR) — Hinges on the right side, opens outward to the left. Verify door handing before ordering. Need Left Hand Reverse? Search for the LHR version of this device.
