For a Washington, DC, condo, office, or storefront, the right high-security lock depends on more than the brand. Compare the exact cylinder’s tested performance, its fit with the existing hardware, how additional keys are authorized, and what it will cost to maintain the system.
Medeco® and Mul-T-Lock® both offer products worth considering. Neither brand name means that every cylinder has the same certification or attack resistance. Ask for the specific model and listing proposed for your door.
Our overview of what sets high-security locks apart covers the basics. This guide focuses on the buying decision.
High Security, Restricted Keys, and Heavy-Duty Hardware
These terms describe different things:
| Feature | What it addresses | What to verify |
|---|---|---|
| Attack-resistant cylinder | Resistance to specified manipulation and destructive attacks | The exact model’s applicable listing or certification |
| Restricted key system | Controls on who can obtain compatible blanks and authorized copies | Dealer authorization procedures, patent status, and recordkeeping |
| Strong lock assembly | The installed lock’s mechanical performance and service life | Applicable product standard, grade, mounting, door, frame, and strike |
A restricted keyway alone does not establish that a cylinder has high-security attack resistance. Likewise, a heavy-duty lockset does not automatically give you controlled key duplication.
What UL and BHMA Ratings Tell You
UL 437 is a standard for specified categories of key locks, including door locks and cylinders. Look for the listing of the proposed product, not a general statement that its brand sells UL-listed hardware. Laboratory testing is not a promise that the entire door will withstand every real-world attack for a stated number of minutes.
ANSI/BHMA A156.30 addresses high-security cylinders, including key control and resistance to destructive and surreptitious attack. Ask which edition and certified performance designation apply to the exact cylinder.
Lockset and deadbolt ratings are separate. Commercial hardware often uses numeric grades under its applicable standard. BHMA’s residential Secure Home program instead rates security, durability, and finish with letters. A residential AAA label should not be confused with a high-security-cylinder designation.
The BHMA high-security-cylinder summary, BHMA residential label explanation, and UL 437 scope describe these different frameworks.
Medeco and Mul-T-Lock: What to Compare
| Buying question | Medeco® | Mul-T-Lock® |
|---|---|---|
| Which current platform is being proposed? | Ask about the exact M4 or other compatible system | Ask about the exact MTL800, MTL600, or other compatible system |
| What physical protection does it provide? | Verify the proposed cylinder’s listing and format | Verify the proposed cylinder’s listing and format |
| How are copies authorized? | Confirm the selected key-control program and its authorization rules | Confirm the selected key-control program and card or authorization requirements |
| Will it fit existing hardware? | Check cylinder format, dimensions, cam or tailpiece, and hardware compatibility | Check the same details for the proposed model |
| What will ownership cost? | Compare installation, replacement keys, rekeying, and support | Compare the same scope and quantities |
Medeco® options
Medeco 4, or M4, is a current mechanical platform with manufacturer-documented UL 437-listed high-security cylinders and patented key-control features. Availability and certification should still be confirmed for the exact format being quoted.
Buildings with existing Medeco systems also need a compatibility and support review before migrating. Replacing every cylinder with a new platform is a different project from adding a cylinder to an existing key system.
For applications needing electronic permissions or audit records, Medeco’s CLIQ® products combine mechanical and electronic functions. Their management requirements differ from a conventional mechanical-key installation.
Mul-T-Lock® options
Mul-T-Lock’s current US lineup includes MTL800 and MTL600.
The manufacturer identifies MTL800 as backward compatible with the previous MT5+ platform and describes a three-part locking mechanism with extensive master-keying options. MTL600 uses telescopic pinning with a floating key element and offers controlled key duplication and multiple cylinder formats.
Older systems may be known by different platform names. Have the installer identify what is already installed and explain whether the proposed work extends it or changes platforms. Do not assume all products under one brand share the same UL listing.
What Restricted Keys Can and Cannot Do
Restricted distribution and an active key-system patent can make unauthorized copying harder. The actual protection depends on the chosen program, who is allowed to order keys, and how the dealer verifies authorization.
A “Do Not Duplicate” stamp alone is not the same as controlled blanks and a documented authorization process. Conversely, “restricted” and “patented” are not interchangeable terms: ask what restrictions and patent protection apply today.
Before choosing a system, ask:
- Who may approve a new key, and what identification or documentation is required?
- Who holds the authorization card or account records?
- How are issued, returned, and missing keys recorded?
- What happens if the authorized dealer closes or the building changes management?
- When does relevant patent protection expire, and what support remains afterward?
Restricted keys do not make duplication impossible, and they do not disable a lost key. If an authorized mechanical key is missing, someone holding it can still use it. Rekeying may be necessary even if no unauthorized copy was ever made.
Master Keys Require a Lost-Key Plan
A master key can operate a defined group of locks while individual keys have narrower access. That convenience increases the consequences of losing a master.
Before installation, document which doors each key can open. Limit master-key holders and agree on the response to a missing key. A lost master may require rekeying every affected opening, whether the keyway is standard or restricted.
For frequent changes of staff or occupants, consider whether managed electronic credentials would suit some doors. Electronic access can allow individual permissions to be changed, but revocation timing and effectiveness depend on the system’s design and update process.
Check the Door and Frame Before Upgrading
Not every opening needs a high-security cylinder. On the privately owned data center cage shown here, which RBD built, the key cylinder is only a backup, so a standard commercial cylinder was the right fit. Matching the hardware to the actual risk keeps the budget where it matters.
A high-security cylinder cannot correct a weak frame, loose strike, damaged door, or unsuitable installation. The assessment should cover the complete opening, including hinges and any exposed hardware.
For storefronts, condos, and apartment buildings, the selected hardware must also preserve required emergency exit, accessibility, and fire-door functions. Reinforcement and replacement parts need to be appropriate for that specific assembly.
RBD installs high-security cylinders and restricted key systems for condos, offices and storefronts, and works with Medeco, Mul-T-Lock, Schlage, Sargent, Yale, Kaba and Lockmasters hardware, along with Von Duprin exit devices. A typical project starts with an inventory of the doors and existing cylinders, then a keying plan showing which keys open which doors, who can authorize new keys, and what happens if one is lost.
Our commercial locksmith service can help assess the opening and the proposed key system. You can also review our lock products.
Frequently Asked Questions
Is Medeco better than Mul-T-Lock?
There is no universal winner. Compare the exact models, relevant certifications, compatibility, key-control procedures, local support, and complete ownership cost.
Can a high-security cylinder fit my existing lock?
Often, a compatible retrofit cylinder is available. The installer must check the lock model, cylinder format, dimensions, operating components, and any assembly requirements.
Can someone copy a restricted key?
A controlled key program reduces opportunities for unauthorized copies, but it is not an absolute guarantee. Verify the program and maintain accurate key records.
Do restricted keys eliminate rekeying after a key is lost?
No. A missing mechanical key can still operate its assigned locks. The response depends on which doors it opens and the circumstances of the loss.
Are high-security locks pick-proof or bump-proof?
Avoid those absolute claims. Look for independently documented resistance to specified attacks and a properly installed door assembly.
Discuss a High-Security Lock Upgrade
Call RBD Security at (202) 709-9466 with your property type, existing hardware, number of doors, and key-control needs. Ask for a proposal that identifies the exact products and the process for obtaining additional keys.
Medeco® and CLIQ® are registered trademarks of Medeco Security Locks, Inc. Mul-T-Lock® is a registered trademark of Mul-T-Lock Technologies Ltd. Both companies are part of the ASSA ABLOY Group. M4, MTL800 and MTL600 are product names of their respective manufacturers. UL is a trademark of UL LLC, and BHMA is a trademark of the Builders Hardware Manufacturers Association. These names are used here only to identify the products discussed. RBD Security is an independent installer and is not affiliated with, sponsored by or endorsed by these companies.