The SRXL 520 pitch chain from EK is a special narrow version of the srx2 chain, with thinner side plates as well as drilled inner plates to minimise weight. the Quadra-X ring design also gives a very low frictional loss while sealing just as effectively as on the regular SRX2 series of chains. Don't run away with the idea that slim chain and light weight results in any weakness. Despite weighing just 1.59Kg per 100 links, the SRXL 520 chain has an ultimate tensile strength of 35.6kN, which out-performs many heavier, bulkier chains.