Fulton Gorilla Guard Trailer Coupler Lock The Fulton Gorilla Guard coupler lock prevents theft and keeps your trailer secure. It features a tamper-resistant design to keep unattended trailers secure. Gorilla Guard is an easy to use, push-button lock. Heavy-duty cast construction with die-cast steel barrel keys ensures long lasting durability. Design shields lock from tampering devices 1 Year limited warranty Specifications 63227 Fits most 2-516 trailer couplers. Good for up to 4-18 wide trailer