This is a Yaban o'ring 520 chain 130 links. We had this chain made for the guys who mainly spend there time dune riding/trail riding and occasionaly drag race, hill climb etc. The o'ring chain will give you longer life compared to our non o'ring chain which is primarily designed for drag racing.
This chain will work with any sprocket combination on a swing arm that is +4 to +8 in length. It is a high tensile strength chain for use with extended swingarms. This is not two chains linked together with two master links it is a one piece one master link chain.
We have tested this chain on engine sizes all the way up to 10mil stroker motors(cub cylinders 68x64) making 120H.P. at the rear wheel with no issues. If you have an engine larger than a 10mil motor of any kind we can not guarantee the life of the chain since we have not tested it ourselves on larger engines. We also recommend with extended swingarms the use of a spring tensioned chain roller as this will help limit the amount of chain flex during hard accelerations.