Master Lock Trailer Coupler Latch Lock — 3.4-inch Shackle, Solid Brass with Chrome Finish and Water‑Tight Cap

Master Lock 1471DAT is a trailer coupler latch lock with a 3.4-inch long shackle and 9/32-inch pin designed to stop the coupler latch from moving and deter unauthorized hitch removal.

This compact coupler lock is built from solid brass with a chrome finish and a water-tight protective cap, made to fit standard UFP and surge brake couplers. Its 4-pin tumbler core, corrosion-resistant plating and weather-tight seal make it a practical choice for owners who need a simple, durable physical deterrent whether the trailer is hitched or stored. The lock works by preventing the latch from operating, blocking both insertion and removal of the trailer ball.

How does this lock secure a trailer's coupler latch?

The Master Lock 1471DAT slips through the coupler latch mechanism so the latch cannot move into an open or closed position. When installed, it physically blocks the path needed to place the coupler onto a ball or to release an attached ball, providing a clear mechanical barrier.

• 3.4-inch shackle length fits across standard latch openings
• 9/32-inch diameter pin matches common coupler holes
• Blocks both insertion and removal of the hitch ball
• Works with UFP and surge brake couplers

What materials and features protect the lock from weather and wear?

The body is cast from solid brass for long service life and the exterior is chrome-plated to resist abrasion and corrosion. A water-tight cap shields the keyway from moisture and grime, and the precision 4-pin tumbler helps maintain operation over time by reducing internal wear.

• Solid brass construction for durability
• Chrome plating for improved corrosion resistance
• Water-tight cap seals the keyway from the elements
• 4-pin tumbler reduces susceptibility to picking and wear

Will this lock fit my trailer coupler?

The 1471DAT is made to standard trailer coupler dimensions: the shackle measures approximately 3-4/10 inches long and the pin diameter is roughly 9/32 inches. These sizes match the common hole spacing and diameters found on most UFP and surge brake couplers, but you should measure your existing latch opening to confirm fit before purchase.

• Shackle length: about 3.4 inches (3-4/10")
• Pin diameter: approximately 9/32" (manufacturer tolerance ±0.05")
• Designed for standard coupler latch holes and spacing
• K1 key blank type—spare keys available from locksmiths or manufacturer

How easy is it to use day-to-day and maintain?

Installation is a simple manual step: insert the pin through the latch and close the shackle or pin, then lock. Routine maintenance is minimal—periodically rinse off road grime, keep the water-tight cap closed, and apply a small amount of graphite or silicone-based lubricant to the keyway if operation becomes stiff.

• Quick manual install and removal with included key
• Simple cleaning to remove dirt and salt after travel
• Cap protects keyway—less frequent keyway lubrication needed
• Chrome finish reduces visible wear for cleaner appearance

Who is this for: Owners of utility trailers, boat trailers, landscape trailers or any tow setup that uses a standard UFP or surge brake coupler and needs a straightforward physical deterrent for the coupler latch. The Master Lock 1471DAT is appropriate for users who want a compact, corrosion-resistant lock that fits typical coupler dimensions and is easy to install and maintain.