The BulletProof Medium Duty Coupler Lock provides cost-effective protection against trailer theft. With a 1/2" hardened solid steel bar and pick-resistant lock, it is a great option for trailer protection. The universal design is compatible with all 1-7/8", 2" and 2-5/16" couplers. All BulletProof locks are treated with an aircraft-grade lubricant for longevity, the locking mechanism is protected by a heavy-duty rubber cap and comes with 2 keys.