High Security: Master Lock Pro Series padlocks provide 120% extra locking force for added security. Keyed Alike: All locks in the set share the same key for convenience and speed. BumpStop Technology: The unique bump stop feature prevents the lock from being bump locked by an intruder. Chrome Finish: The durable chrome finish resists corrosion and rust. Hand Control: The padlocks are operated using a hand control for easy access. FEATURING BumpStop TECHNOLOGY - Lock bumping - a surprisingly simple method of breaking in through locked doors and padlocks - is undoubtedly the newest emerging threat to personal property security. And virtually all locks in use today are particularly vulnerable to bumping. Until now. BumpStop Advanced Cylinder Technology employs an innovative, patent pending design which utilizes a unique reverse rake tapered driver pin, high performance springs and tightly machined cylinder chambers. During a bump attempt, this design prevents the transfer of force from the bump key to the pins and therefore blocks rotation of the cylinder so that the lock remains locked.