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Master Lock 378DAT Adjustable Universal Coupler Lock for 2-5/16 Inch Trailer Couplers

Manufacturer

Master Lock

<h3>A Century of Security Innovation</h3><p>Since 1921, Master Lock has been synonymous with strength, durability, and uncompromising security. Founded by locksmith-inventor Harry Soref, the company revolutionized the industry with a padlock design that used laminated steel layers to economically produce an exceptionally strong lock body. Now a subsidiary of Fortune Brands Innovations, Master Lock Company LLC is headquartered in Oak Creek, Wisconsin, where it continues to develop security solutions trusted by millions around the world.</p><p>The brand gained widespread recognition through its famous 1974 Super Bowl commercial showing a blast from a high-powered rifle aimed at a padlock—though the bullet pierced the lock, it still functioned, cementing the "Tough Under Fire" slogan in the American consciousness. That commitment to legendary strength remains the foundation of every Master Lock product today.</p><h3>Comprehensive Security Solutions</h3><p>Master Lock's extensive product lineup serves diverse security needs across personal, automotive, commercial, and industrial applications. At the core of the brand's reputation are its <a href="/436-master-lock-locks-200628">locks</a>, which range from classic laminated padlocks and combination locks to cutting-edge Bluetooth-enabled and biometric models. The company added the combination lock to its portfolio in 1935, a model still sold today, and launched Bluetooth-enabled padlocks in 2015, demonstrating Master Lock's ability to honor tradition while embracing innovation.</p><p>Beyond traditional security, Master Lock has expanded into automotive and cargo control solutions. Their <a href="/436-master-lock-tie-strap-and-clip-10142">tie straps and clips</a> help secure loads in truck beds, trailers, and roof racks, featuring innovations like the StrapTrap system that manages excess webbing. For vehicle security, Master Lock offers specialized products including <a href="/436-master-lock-spare-tire-hoist-20541">spare tire hoists</a> and spare tire locks for automobiles, protecting vulnerable external-mounted tires from theft.</p><h3>Built to Last</h3><p>What sets Master Lock apart is not just product innovation but enduring quality. Customer testimonials speak of locks protecting spare tires during 8,300-mile trips to Alaska and combination locks working flawlessly after 64+ years of service with exposure to the elements. This extraordinary longevity stems from Master Lock's commitment to rigorous testing and premium materials, whether it's high-security shackles on padlocks or UV-treated polyester webbing on cargo straps.</p><p>Whether you're securing a storage unit, protecting tools at a job site, locking down cargo, or safeguarding your vehicle's spare tire, Master Lock delivers the authentic, time-tested security that has made it a household name for over a century. When protection matters, professionals and homeowners alike turn to the brand that literally proved it's tough under fire.</p>

Part Number

378DAT
06/03/2036 7:30 AM
Sale Price

$67.60

In Stock (10+)

delivery box

Usually delivered within 2 days

free shipping

FREE SHIPPING

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No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Master Lock 378DAT is an adjustable universal coupler lock designed to protect trailers, RVs, boats, and other towable equipment from theft. This heavy-duty security device fits standard 2-5/16 inch trailer couplers and features a hitch ball and clamp-type locking mechanism that provides robust theft deterrence when your trailer is parked or in storage.

Key Features:

  • Fits 2-5/16 inch trailer couplers for universal compatibility
  • Adjustable design accommodates various coupler sizes and styles
  • Advanced locking mechanism with hardened steel construction
  • Hitch ball and clamp-type system for secure attachment
  • Bright yellow finish provides high visibility as a theft deterrent
  • Weather-resistant design for outdoor use

This coupler lock installs quickly over the trailer coupler, preventing unauthorized hitching and towing. The adjustable design ensures a snug fit on different coupler configurations, while the advanced locking cylinder provides pick resistance and security. An essential accessory for protecting your investment when your trailer is unattended.

Products specifications

Coupler Lock Finish

Nickel plated

Coupler Lock Material

Steel

Lock Type

Coupler lock

Locking Keys Included

Yes

Quantity

Sold individually.

Been looking for these everywhere Thank you Don

Couldn't call to check predicted shipping arrival date.

So far so good.....I can't believe the price on the tires I just ordered; almost too good to be true......

Fast shipping

Great job.

very good so far

Thanks. I'll be back!

Fast and easy

so far so good didn't receive the product yet &gt;&gt;?

Easy web searching and good quality parts for reasonable price..customer friendly too!!!!!!

Great selection and fast shipping. Not to meantion the lowest prices anywhere on the net.

Excellent Service! Product shipped out the day after being processed and was sent via overnight delivery. Autoplicity also offered the lowest cost available for the product online.

Very good prices and incredibly fast shipping. Shipping costs were a bit high but I would definitely use them again!

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