We need to build a 40G-10G connection. After consulting with my account manager, we find this AOC harness cable is better for our needs. We prefer fiber than copper, and we want to reuse our existing 10G transceivers. Now it turns to be a total success. Our system is running like a gear with no disconnection. At first, we were worried about the joint between the transceiver and the fiber, as we bought such harness cable elsewhere before that was loose and finally broke. But everything is different with FS. We are assured by their quality commitment. Sure enough, we have got the perfect AOC cables from FS. Highly recommend.