CURT 23521 Black Trailer Tongue Coupler Lock – One-Quarter Inch Pin, Three-Quarter Inch Span, Two Keys

Protect your trailer with the CURT 23521

Every trip, campsite, or marina parking spot comes with a risk to your trailer. The CURT 23521 Black Trailer Tongue Coupler Lock adds a strong layer of protection by transforming a standard latch-type coupler into a lockable connection. Built with high-strength steel and finished in a durable black coating, this lock is designed to withstand outdoor use and deter tampering in real-world conditions.

What makes it work

The padlock-style form creates a visible, robust barrier around the lock mechanism. A simple one-quarter-turn action allows for quick locking when you’re in a hurry and a swift unlock when you’re ready to move.

• DEPENDABLE SECURITY. High-strength steel construction paired with a padlock-style design helps deter tampering while your trailer is connected to your vehicle.
• EASY TO OPERATE. The lock activates with a quick one-quarter-turn, making locking and unlocking straightforward on the go.
• VERSATILE FIT. The one-quarter inch pin diameter fits latch-type couplers with a span up to three-quarters of an inch.
• WEATHER-RESISTANT. A black finish protects the lock from the elements, with a corrosion-resistant pin for outdoor use.
• TWO KEYS INCLUDED. Two keys offer convenience and a spare for emergencies.

Real-world use cases

Whether you’re anchoring a boat at a marina, towing a camper across town, or hauling a utility trailer for a DIY project, CURT 23521 adds a visible deterrence and a locking option that can stay in place during transit and be quick to remove at your destination.

Specs and maintenance at a glance

• Pin diameter: one-quarter inch
• Span: up to three-quarters of an inch
• Finish: black weather-resistant coating
• Includes: two keys

Care and maintenance: wipe away moisture after exposure to rain or salt water, and store spare keys in a discrete location to ensure ready access when needed.

Why choose CURT

CURT is known for practical towing accessories built to perform. This coupler lock complements CURT safety pins and latches by adding an additional locking layer, helping protect your trailer when parked or in transit. While no single lock guarantees theft prevention, the CURT 23521 is designed to make tampering more difficult and time-consuming.