Master Lock 379KA-4: Four Keyed-Alike Universal Trailer Coupler Locks with 8 Keys

Protect multiple trailers with one key

The Master Lock 379KA-4 kit is a four-pack of keyed-alike trailer coupler locks designed to simplify security for a fleet, a storage yard, or a property with several trailers. With a single keying system across all locks, you can operate every lock without juggling different keys. Each lock ships with two keys, giving you eight keys in total for ongoing use and spare access.

Designed for real-world usability

The locks guard unattended trailers and help deter tow-away attempts. The universal design fits common 1-7/8 in, 2 in, and most 2-5/16 in couplers used by Reese, Fulton, Valley, Atwood, Shelby, Putnam, Hammerblow, Dutton, Lainson, and UFP.

The clever geometry places the lock on top of the coupler when locked, making blunt-force entry more difficult. The lock also rotates slightly, adding an extra hurdle if someone tries to break in with heavy tools.

Strength, durability and long-term value

Constructed with reinforced zinc die cast, these locks resist rust and corrosion while delivering high strength. The kit is designed for repeated use in challenging conditions and remains relatively lightweight for easy handling during installation and removal.

• Keyed-alike convenience: one key opens all locks; eight keys included
• Broad compatibility: fits 1-7/8 in, 2 in, and 2-5/16 in couplers from major brands
• Durable construction: reinforced zinc die cast for improved strength and formability
• Security design: lock sits on top of the coupler and rotates to resist forced entry
• Easy to use: rekeyable cylinder with simple installation; about 2.4 lb per lock
• Warranty: Limited Lifetime warranty

In the box

• Four keyed-alike trailer locks
• Eight keys total
• Limited Lifetime warranty

Ordering notes

If you order two four packs, they may not be keyed the same. For guaranteed keyed-alike compatibility, consider the eight-pack option.