Master Lock 387KA-3416 King Pin Trailer Lock

Product Description

The MASTER LOCK 387KA-3416 is a king pin lock designed to secure semi-trailer fifth-wheel coupling points. It locks directly onto the trailer king pin, preventing unauthorized coupling and deterring theft or accidental hookup in yard and staging environments. The lock body is constructed from aluminum, keeping overall weight manageable while maintaining structural integrity at the coupling interface. At 6.5 pounds, it is a heavy-duty mechanical security device intended for installation by fleet operators, yard workers, and transportation professionals working with standard semi-trailer configurations.

This king pin lock is used on semi-trailers in commercial freight, logistics, and transportation applications. It is suited for yard storage security, drop-and-hook operations, and any scenario where a trailer must remain stationary and uncoupled. Typical use cases include distribution center yards, truck terminals, and fleet staging areas where trailers are left unattended for extended periods. The lock engages the king pin directly, requiring no additional hardware or tools beyond what comes with the unit.

Key Features

• Aluminum construction reduces weight while providing durable protection at the king pin
• Designed specifically for semi-trailer king pin applications
• Prevents unauthorized fifth-wheel coupling when trailer is parked or staged
• Keyed configuration (KA designation indicates keyed alike) for fleet key management
• Compact, self-contained unit with no additional mounting hardware required

Compatibility

Designed as an OEM-style replacement and standard fitment for semi-trailers equipped with conventional king pins used in fifth-wheel coupling systems.

Installation Notes

Installation is performed by fleet maintenance personnel or yard operators and requires no special tools. Ensure the trailer is fully uncoupled and stationary before engaging or removing the lock. Inspect the king pin for damage or wear before installing the lock to confirm a secure fit. Follow all applicable DOT and fleet security guidelines when using king pin locks for trailer immobilization.