Hager 3981-U Small Format Inte...
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$53.03
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Hager 3981-U Small Format Interchangeable Core, Uncombinated, 6 Pin with Best Keyways in Satin Brass

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Model: 3981-U US4

In Stock (leaves warehouse same day if ordered before 3pm ET)

$53.03
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Hager 3981-U Small Format Interchangeable Core, Uncombinated, 6 Pin with Best Keyways in Satin Brass

The Hager 3981-U is a Small Format Interchangeable Core (SFIC) designed for commercial door hardware applications requiring flexible, tool-free core replacement. Delivered uncombinated with 6-pin configuration and Best keyways, this IC core is finished in Satin Brass and is engineered to integrate seamlessly into compatible Hager lock cylinders. Its interchangeable core format allows facilities managers and security professionals to re-key or replace cores quickly without removing the lockset from the door, making it an ideal solution for high-security or multi-tenant environments.

Key Features

  • Small Format Interchangeable Core (SFIC): Tool-free core interchange allows rapid re-keying or core replacement without lock disassembly, reducing downtime and maintenance costs in commercial facilities.
  • Uncombinated Configuration: Shipped uncombinated, allowing locksmiths and security professionals to pin and key the core to specific master key system requirements on-site.
  • 6-Pin Cylinder: Six-pin tumbler design provides enhanced security and broader key combination potential for demanding commercial access control applications.
  • Best Keyways Compatibility: Engineered to accept Best keyways, ensuring compatibility with Best-format key systems widely used across commercial and institutional facilities.
  • Satin Brass Finish: Durable Satin Brass finish provides a professional aesthetic and corrosion resistance suited for interior commercial door hardware applications.
  • Commercial-Grade Construction: Built to meet the rigorous demands of commercial environments, supporting reliable, long-term performance as a replacement part for Hager lock systems.
  • Hager Lock Parts Compatibility: Designed as a genuine Hager replacement part, ensuring proper fit and function within compatible Hager lock products.

Technical Specifications

  • Department: Door Hardware
  • Product Category: Mechanical Locks
  • Product Group: Parts and Accessories
  • Subcategory: Parts and Accessories
  • Product Subgroup: Parts and Accessories
  • Product Type: IC Core
  • Parts and Accessories Type: Replacement Parts
  • Commercial/Residential: Commercial
  • Product Model: 3981-U
  • Features: Hager Lock Parts

Typical Applications

  • Commercial Office Buildings
  • Educational Facilities and University Campuses
  • Healthcare Institutions and Medical Facilities
  • Government and Municipal Buildings
  • Multi-Tenant Residential and Mixed-Use Properties
  • Industrial and Warehouse Facilities
  • Retail Establishments Requiring Master Key Systems

Why Hager 3981-U?

The Hager 3981-U delivers professional-grade reliability as a genuine replacement IC core engineered for compatibility with Hager lock systems. Its uncombinated, 6-pin, Best keyway format offers security professionals maximum flexibility for custom key system integration. Designed specifically for commercial applications, this interchangeable core supports efficient facility management and dependable access control performance.

Manufacturer Resources

Product Specs

Department:
Door Hardware
Product Category:
Mechanical Locks
Product Group:
Parts and Accessories
Subcategory:
Parts and Accessories
Product Subgroup:
Parts and Accessories
Product Type:
IC Core
Parts and Accessories Type:
Replacement Parts
Commercial/Residential:
Commercial
Product Model:
3981-U
Features:
Hager Lock Parts

Hager 3981-U US4 – Frequently Asked Questions

1) Will a Best-keyway key blank work in the Hager 3981-U core?
Yes. The 3981-U is built to accept Best keyways, so if your facility already runs a Best-format key system the blanks and bitting you use now apply. It is a 6-pin core, so order 6-pin blanks and pin kits to match.
2) What is a small format interchangeable core and why would I use one over a fixed cylinder?
An SFIC is a figure-eight core that drops into a compatible housing and comes back out with a control key, no tools and no pulling the lockset off the door. That is the whole reason to spec it: re-keying a tenant turnover or a lost-key event becomes a core swap at the door instead of a lock teardown. A fixed cylinder has to be removed and repinned. The 3981-U is the SFIC version, uncombinated so you set the keying.
3) Can I put this core in my Schlage or Sargent locks, or only Hager?
The 3981-U is a genuine Hager replacement core intended for compatible Hager lock cylinders. Because it is a small format interchangeable core with Best keyways, it fits SFIC housings prepped for that standard figure-eight core, which is the common commercial interchange. What it will not fit is a large format interchangeable cylinder. Schlage's own large format core, for example the Schlage Commercial 20-207 FSIC core in the S123 keyway, is a different body entirely and is not a substitute either direction.
4) Is the 3981-U 6-pin or 7-pin, and does it matter for my master key system?
Six pin. It matters: a 6-pin SFIC housing and a 7-pin housing use different core lengths, and a 6-pin core will not key into a system built on 7-pin bitting. Confirm your existing cores are 6-pin before you standardize on these, and order 6-pin bottom pin and master pin kits for the build.
5) Will a Schlage 20-207 core drop into a lock prepped for the Hager 3981-U?
No. The Hager 3981-U is a small format interchangeable core (SFIC) cut for Best keyways, while the Schlage Commercial 20-207 is a sub-assembled FSIC core in the S123 keyway. The two use different core formats and different keyways, so a housing prepped for the small format Hager core will not accept the Schlage part. If the opening is keyed into a Best-format system, stay with the 3981-U; if the building is on Schlage S123, the 20-207 is the core that matches that system.
6) What is the difference between an SFIC core and the LFIC core Schlage sells?
The Hager 3981-U is a small format interchangeable core, the six-pin figure-eight style core used across Best-format systems and removed with a control key without taking the lock off the door. The Schlage Commercial 20-207 is listed as an LFIC core, the large format style, which needs a housing machined for that larger core. They are not interchangeable in the same lock body, so match the core to the prep already in the lockset rather than to the brand on the door.
7) I need to match satin brass hardware on the rest of my doors. What finish is this core?
Satin brass, BHMA finish code 606. That is the only finish offered on the 3981-U, so if your other openings are chrome or bronze the core face will not match once it is installed.
8) What else do I need to order with these cores to get a building keyed?
The cores alone won't finish the job. Uncombinated means you supply the pinning: bottom pins, master pins and springs in 6-pin sizes, plus cut key blanks in your Best keyway. You also need a control key for the core interchange itself, and the lock housings have to already be prepped for a small format interchangeable core. Nothing in that list ships with the 3981-U.
9) I need a core I can pin to my own master key system - which one comes ready to key?
The Hager 3981-U ships uncombinated, so a locksmith pins and keys it on site to whatever master key system the building runs, in a 6-pin Best keyway format. The Schlage Commercial 20-207 is a sub-assembled FSIC core in the S123 keyway, which fixes it to the Schlage S123 key system. Choose the 3981-U when you are building or extending a Best-format masterkey system and want the pinning done in your own shop.
10) Is this core rated for commercial traffic or is it a residential part?
Commercial. Hager catalogs the 3981-U as a commercial mechanical lock replacement part, and the typical uses are office buildings, schools and campuses, healthcare, government buildings, multi-tenant residential, warehouses and retail running master key systems.
How fast can I get the Hager 3981-U US4 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Hager 3981-U US4 come with a warranty?
Absolutely. The Hager 3981-U US4 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Hager 3981-U US4?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Hager 3981-U US4 from ZenSupply?
ZenSupply makes it easy to get the commercial door hardware you need—fast shipping, expert support, and rewards on every order. Our team is always ready to help you choose the right product for your project.
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