Master Lock Universal Trailer Coupler Lock 379KA - Keyed Alike

Our review of the Master Lock Universal Trailer Coupler Lock 379KA finds it best suited for trailer owners who need a simple, reliable way to prevent tow-away theft. The single biggest reason to buy is straightforward: it offers broad fitment for 1-7/8 in, 2 in, and 2-5/16 in couplers while using an advanced locking mechanism that resists picking and prying. Installation and removal are easy, and the keyed alike option makes it practical for users managing multiple trailers or hitches without juggling multiple keys.

Key Features

• Universal Fit: Fits 1-7/8 in, 2 in, and 2-5/16 in couplers so one lock covers most common trailer tongues.
• Advanced Locking Mechanism: The lock resists picking and prying, improving security for unattended trailers.
• Keyed Alike Convenience: Sold keyed alike so two or more locks can be operated with the same key, easing management of multiple trailers.
• Durable Construction: Weighing 2.4 lbs, the lock is built to feel substantial and resists rust and corrosion for outdoor use.
• Rekeyable Design: The mechanism is rekeyable through an authorized Master Lock locksmith for users who want to change keys later.
• Lifetime Warranty: Limited lifetime warranty provides long-term assurance against defects and manufacturing issues.

Who It's For

The 379KA is ideal for owners of utility, boat, or equipment trailers who want one lock that fits multiple coupler sizes and prefer the convenience of keyed alike units. It works well for fleet owners, rental operators, and homeowners who move trailers between hitches and want consistent key access.

Those who need a low-profile or permanently mounted coupler lock, or who require high-security solutions rated against cutting with heavy tools, may want to consider specialized hitch immobilizers or additional chains and devices. This lock is focused on deterring opportunistic theft and providing practical everyday security.

Pros & Cons

Pros

• Broad compatibility across common coupler sizes reduces the need for multiple lock types.
• Advanced locking mechanism and resistance to picking and prying increase theft deterrence.
• Keyed alike option and two included keys simplify use across multiple trailers.
• Corrosion resistance and a limited lifetime warranty add long-term value.

Cons

• Some customers report mixed impressions of build durability, so extreme abuse or severe cutting attacks are not guaranteed to be stopped.
• The weight and size may be bulkier than slim-profile alternatives if space is limited.

Specifications

Model	379KA
Compatibility	Fits 1-7/8 in, 2 in, and 2-5/16 in couplers
Weight	2.4 lbs per lock
Keying	Keyed alike, includes two keys
Corrosion Resistance	Resists rust and corrosion
Rekeyable	Yes, by authorized Master Lock locksmith
Warranty	Limited lifetime warranty

Our Verdict

The Master Lock 379KA universal coupler lock is a practical, good-value choice for everyday trailer security, especially for users who need one lock to fit multiple hitch sizes and prefer keyed alike convenience. It balances ease of use, corrosion resistance, and an advanced locking mechanism, making it a sensible deterrent against theft for most owners, while those needing extreme cut resistance should supplement it with additional security measures.

Frequently Asked Questions

Will this lock fit my trailer coupler?
It fits 1-7/8 in, 2 in, and 2-5/16 in couplers from common manufacturers, covering the most widely used trailer tongues.

Are the locks rekeyable?
Yes, the locking mechanism is rekeyable through an authorized Master Lock locksmith if you need to change keys later.

How many keys are included?
The listing includes two keys and the keyed alike option makes it easy to use the same key for multiple locks.