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

Master Lock

<h3>Master Lock: A Century of Security Innovation</h3><p>Few names carry as much weight in the world of security as <strong>Master Lock</strong>. Founded in 1921 by Harry Soref in Milwaukee, Wisconsin, the company was built on a genuinely novel idea: a padlock with a laminated steel body that delivered dramatically greater strength and resistance to forced entry than anything available at the time. More than a century later, Master Lock — now headquartered in Oak Creek, Wisconsin — remains the benchmark against which other security products are measured.</p><p>While most people know Master Lock for the combination padlocks hanging in gym lockers and on job-site gates, the brand has expanded its expertise into the world of towing, trailering, and cargo management. For anyone who regularly hauls boats, campers, ATVs, motorcycles, or utility trailers, Master Lock's automotive and towing lineup brings the same uncompromising approach to security to the open road.</p><h3>Trailer Security You Can Trust</h3><p>Master Lock's <a href="/436-master-lock-trailer-hitch-lock-14537">trailer hitch locks</a> represent the heart of the brand's towing security lineup. These purpose-built locks are engineered to resist weather and corrosion — a critical requirement for hardware that lives outdoors through rain, road salt, and temperature swings. Options include coupler locks that prevent unauthorized hitching of your trailer, receiver hitch pin locks that replace standard hitch pins with lockable alternatives, and keyed-alike combo sets that let one key secure your entire rig. Swivel-head designs make access easier even when trailer wiring limits the available angle.</p><p>Beyond the coupler, Master Lock also addresses the hitch itself. Their <a href="/436-master-lock-trailer-hitch-1212">trailer hitch</a> hardware — including stainless steel pivot-lock hitch pins and receiver locks — is designed to fit Class III and Class IV setups, with tapered ends for easy insertion and solid construction that stands up to real towing loads. Whether you&apos;re securing a ball mount or protecting a drawbar, these products bring the brand&apos;s foundational security DNA directly to the tow vehicle connection point.</p><h3>Cargo Control with a Security Mindset</h3><p>Keeping a trailer attached to your vehicle is only half the job — keeping the cargo secured in the trailer is the other. Master Lock&apos;s <a href="/436-master-lock-tie-strap-and-clip-10142">tie straps and clips</a> apply the same engineering rigor to cargo control. Their ratchet tie-down straps feature Monster Weave™ webbing for exceptional tensile strength, Razor Coat abrasion-resistant protection for long service life, and S-hooks with integrated retention clips that prevent the hook from slipping off its anchor point even when tension is released. The proprietary StrapTrap™ bungee cinch manages excess strap length neatly, eliminating the flapping and tangling that plagues standard tie-downs.</p><h3>Why Master Lock for Towing and Trailering?</h3><ul style="list-style:disc"><li>Over 100 years of security engineering heritage</li><li>Weather- and corrosion-resistant construction on all towing hardware</li><li>Broad compatibility — coupler locks that fit 1-7/8 in., 2 in., and most 2-5/16 in. couplers</li><li>Keyed-alike options let a single key secure receiver lock, coupler lock, and ball mount lock</li><li>Proprietary webbing and clip technologies in tie-down straps for real-world reliability</li></ul><p>Whether you&apos;re a weekend warrior towing a boat to the lake or a professional hauling equipment daily, Master Lock&apos;s towing and trailering products deliver the confidence that comes with a name that has been synonymous with security for generations.</p>