12mm, 6-sided chain links made of 3t manganese steel provide maximum strengthCinch ring design enables effective lock up with less length of chainDurable, protective nylon cover with hook-n-loop fasteners to hold it in placeEvolution series 4 Disc Lock features a 14mm hardenedMAX-Performance steel shackle with double deadbolt locking for additional protection against twist attacksPatented, hardened oval crossbar design is stronger than a typical round tubeHigher security disc cylinder includes an anti-float feature to keep discs from moving when in transitIncludes 3 keys: 2, I keys and one with a high-intensity L.E.D. bulb for convenient, easy unlocking in the dark$1000 Anti-Theft Protection offered by manufacturerKey Safe Program; key registration and replacement