Kryptonite’s KryptoLok Series 2 955 Mini Integrated Chain is a 9mm-thick, four-sided link chain made of triple-heat-treated manganese steel for serious strength. Its integrated high-security lock cylinder is pick, drill, and cut resistant. This 21.5-inch chain is covered with a weather-resistant nylon sleeve that protects your bike’s finish. Plus, the KryptoLok Series 2 has an anti-theft protection offer.