ONGUARD 8021 Mastiff 6-Foot x 3/8-Inch Heavy Duty Quad Bike Chain Lock - Secure Bicycles, Motorcycles & Outdoor Equipment - Ideal for Urban Commuting, Parking & Storage Protection

Awesome chain. It will delay potential bike thieves much longer than most cables/wires that are on the market. Its heavy fabric outer covering protects my car's roof from scratching. It comes with 4 keys, too, unlike some other famous companies that give you 2 keys, and then charge exorbitant fees for additional keys/lock heads. (Yakima can you read this please.)I have a 2-bike roof rack system, and I will buy a 2nd Mastiff to protect another bicycle. The chain is very heavy and not long enough to securely protect 2 bikes, however, it will secure 1 bike.