Bought the lock and chain as it was on special from REI and looked very secure and heavy. It was to chain my and my wife's two bikes in an underground parkade. The chain is a beast just like it says and will probably be impervious to bolt cutters. The lock however is cheaply made and actually fell apart when I opened the box. When I picked it up at REI the box was sealed, so obviously it was a fault direct from the manufacturer. I had to re-assemble the lock. It works ok, but key locking is finicky. I have since purchased an Abus Granite lock and it is a much better quality product. Key use is smooth and feels accurate. I still use the chain, but with my Abus lock.