Tough as Nails Theft Protection You Can Trust: Folks in the transportation, marine, and RV industries know they can count on this lock. Its high - grade carbon steel body and powder - coated armor have been tested against sledgehammers, grinders, and freeze attacks. Whether you're at an unlit dock or a crowded truck stop, this lock's proven resilience can outsmart even the most experienced thieves. It safeguards trailers, campers, and boats just like the ones in Fortune 500 fleets, keeping the ball of your trailer secure. Quick & Easy Locking with Unbreakable Keys: Designed for heavy - duty use, the patented push - button puck lock secures your coupler in seconds without needing a key to lock it. When you need to unlock, just use one of the 3 theft - proof keys. They have anti - pick grooves and drill - defying pins, making it easy to unlock. The internal blocking mechanism stops lock - picking and key duplication, a feature that security industries use to protect valuable assets. Perfect Fit for 2-5/16" Heavy Duty Couplers: This lock is precision - designed for industrial trucks, boat trailers, and commercial RVs. It eliminates the gaps that thieves often target. Its exclusive 2-5/16 inch compatibility meets the tough requirements of the construction, logistics, and marine industries. It ensures a tamper - proof seal on couplers that professionals trust. Make sure to check your tongue coupler type and size before you buy. Weather Resistant Beast for Harsh Conditions: This lock can handle anything from coastal salt spray to Arctic blizzards. Its corrosion - resistant powder coat and sealed core keep it working where other locks might fail. The bright silver finish is a proven visual deterrent at job sites, marinas, or remote camps. Thieves know it's a strong lock and will think twice before trying anything. Upgraded Design for Real World Use: We've reengineered this lock with more chain storage and full - coverage shielding to address the concerns of truckers and boat owners. Its streamlined profile fits perfectly on commercial - grade hitches, and the rugged build can handle the daily wear and tear of industrial use. You can sleep soundly knowing your gear is protected by a security system that's been proven in various industries. No need for bulky tools or wasting time.