Marks USA G3 145K Single Cylinder Deadbolt Grade 1 Defender Cylindrical Cartridge Deadlatch, Less Cylinder

Marks USA 145K Single Cylinder Deadbolt Grade 1 Defender Cylindrical Cartridge Deadlatch, Less Cylinder

The Marks USA 145K is a Grade 1 single cylinder deadbolt featuring the Defender Series cylindrical cartridge deadlatch, engineered for commercial-grade security and versatile cylinder compatibility. Designed for 1-3/4" door thickness (with spacer rings K1442/32D available for 1-3/8" doors), this unitized assembly installs into a standard 2-1/8" bore and accepts most manufacturers' conventional cylinders as well as high-security options from Medeco, Kaba, Multilock, and ASSA. The deadlatch carries an ANSI 156.5 Grade 1 rating with a UL 3-hour fire rating, while the deadbolt meets ANSI 156.5 Grade 1 standards, making this a dependable choice for demanding commercial applications.

Key Features

• ANSI 156.5 Grade 1 Deadlatch: UL fire rated for 3 hours, providing certified protection for commercial fire-rated door assemblies.
• ANSI 156.5 Grade 1 Deadbolt: Meets the highest ANSI grade standard for commercial deadbolts, ensuring robust security performance.
• Latch Specifications: Grade 1 latch with 9/16" throw and 2-3/4" backset; latch front measures 1-1/8" x 2-1/4" for precise door preparation.
• Unitized Assembly for 2-1/8" Bore: Series 1 cylindrical cartridge design installs easily into a standard 2-1/8" bore for straightforward retrofits and new installations.
• Broad Cylinder Compatibility: Accepts Medeco, Kaba, Multilock, ASSA, and other high-security cylinders, as well as most manufacturers' conventional cylinders and IC core models for "Best" size cores.
• Tapered Cylinder Collars: Engineered to prevent break-in attempts by wrenching, adding a critical layer of physical attack resistance.
• Steel Shutter System: Eliminates access to mounting screws when the door is locked, protecting against tampering and unauthorized disassembly.
• Door Thickness Flexibility: Standard fit for 1-3/4" doors; compatible with 1-3/8" doors using spacer rings K1442/32D.
• Multiple Functions Available: Available in K (Cylinder x Turnpiece), L (Communicating Single Cylinder), M (Double Cylinder), KL (Cylinder x Lever), X (Turnpiece x Blank Plate), and KK (Cylinder x Knob) configurations.
• Finish Options: Available in Bright Brass (3), Stainless Steel (32D), Dark Bronze (10B), and Satin Chrome (26D) to suit a variety of architectural requirements.

Certifications & Compliance

• ANSI 156.5 Grade 1 — Deadbolt
• ANSI 156.5 Grade 1 — Deadlatch
• UL Fire Rated — 3 Hours (Deadlatch)

Technical Specifications

• Latch Front: 1" x 2-1/4"
• Product Group: Mechanical Locks
• Product Subgroup: Bored Locksets
• Subcategory: Cylindrical Locks
• Commercial/Residential: Commercial
• Keyed: Yes
• Product Function: Cylinder x Thumbturn
• Latch Type Specification: Deadlocking
• Keyway Profile: Less Core
• Product Category: Mechanical Locks
• Department: Door Hardware

Typical Applications

• Commercial Office Buildings
• Educational Facilities
• Healthcare Institutions
• Retail Establishments
• Industrial and Warehouse Facilities
• Multi-Tenant Residential Properties
• Government and Municipal Buildings

Why Marks USA 145K?

Marks USA 145K deadbolts and deadlatches are built to meet the rigorous demands of commercial door security, combining ANSI 156.5 Grade 1 certification with a UL 3-hour fire rating on the deadlatch for verified performance in life-safety applications. The Defender Series cylindrical cartridge design incorporates tapered cylinder collars and a steel shutter system to resist physical attack, while broad cylinder compatibility ensures seamless integration with virtually any keying system in use today.