This is a Via Velo bike lock which is heavy duty. It has a U lock which has a mountain bracket suitable for 20-42mm bike tubes. There is also a 180cm cable which is covered in PVC which means that it will not scratch or otherwise damage your bike or what it is attached to but will still be cut resistant. It comes with a set of two keys to go with it so that you have a spare in case you lose one of them and can keep one with you and one safely at home. It is very simple to install and means that you can keep your bike safe and secure wherever you are.