This is a chain lock that I used for my bicycle. It comes with two keys. The length is about 1 meter. The chain is covered, so I can't tell how thick it is, but it's not very thick. The cover for the keyhole requires a bit of a trick to open. It should be good for preventing theft. - Color: Black and yellow - Key: Yes - Lock Type: Chain lock - Material: Chain with nylon cover Thank you for looking.