The camshaft timing chain as used in the later model Mini & Mini Cooper have a simplex single row. This single row chain is very similar to the one used in al the early Mini and some Mini Cooper. The main difference with this late model version is the use of a tensioner. This tensioner insures that the slack that will occur after time is minimized. It is one of those inexpensive things that just should be replaced every time you open the motor of the your Mini Cooper.