Special superb extra strong timing chain with very limited stretch using modern day materials and technology to keep your timing correct and will fit any A series engine using a single row chain.
This chain saves all the time and effort required replacing standard chains and is definitely worth every extra pound of cost.
A tensioner kit with this chain is available as MSSK051EVO
A few well known race engine builders use this chain and single wheel set up saving some weight and problems with timing covers fouling as often encountered with duplex chain set ups.
The twin row chain duplex gear set introduced on Cooper S engines uses 2H4905EVO. Check your timing gears for wear. Please note that the cam gear with the tensioner rings was superseded by the plain gear which is the only type available. This chain works superbly on A plus tensioner type engines even if tuned and is worth the extra expense for longevity.