We first added the 40km QSFP+ module and fiber attenuators into the shopping cart. When the FS guy confirmed our order list with us, he said we didn’t need to buy the attenuators if our link was 20km. Then we only buy the modules, and did a test after we received them. They performed well on our Cisco device. Thank you for helping us save unnecessary expenditure.

The two modules arrived with good protection and work flawlessly in our Cisco Nexus 3064 switch.

Products are fully functional and received in perfect condition. Great price compared to the OEM ones!

We have a Cisco Nexus 9236C in our head office, and one Nexus 92160YC-X switch in another office far away from the head. We needed 40G modules to make a direct connection between them. I took a chance and purchased several of FS modules and cables to do the links. When the two Cisco switches were connected, no issue happened. They run nice and cool for us, and we have 0 dropped packets. FS technical team was very responsible. They kindly reminded us that we’d better deploy fiber optic attenuators for our 15km link, so as to ensure the link could work normally. So we bought the fiber attenuators with 5dB. All work great, and more time will tell if these are rock solid.

We needed to upgrade some links to 40G with no WDM, just transceivers-fiber pair-transceivers. FS team first asked us our networking environment, and confirmed the link loss. Then they recommended us these 40G ER4 modules, and explained that 40G LR4 10km modules might not meet our link budget (we planned to buy the 40G LR4 modules). We also purchased some fibers and horizontal cable managers, to clean up our chaotic cables.
We are in America, and concerned about the delivery. FS told us they worked with UPS in America, and the items would be delivered on schedule and arrive on time. Actually, they did, and there was no damage on the outside packing. All products worked as advertised.

We use Cisco 9500-16 2Q for 10G downlinks, and Cisco 9500-32 QC for 40G links. We needed some 10G and 40G modules, fibers and cable management tools. At FS, we could buy these all, instead of buying fibers from one vendor, and tools from another vendor. At FS website, I found there was FS box that seemed to solve compatibility issues. Maybe I will try when I need to code the modules.
When I received the items, I was surprised by the packing. The 10G modules came in a nice protective plastic box, each was secured tightly in place, and the 40G modules were packaged separately in one plastic box. Outside the plastic box, it was hard cardboard. The package was as solid as we never expect. All products have worked flawlessly in our Cisco switches.

We were planning a data center project about two months ago. A large number of transceivers and cables were needed. After balancing all the factors we should consider, we turned to FS. That was the right decision indeed. For transceivers, the ER4 modules we've bought were wrapped meticulously and remained undamaged through the long delivery. ALL of them worked smoothly with Cisco Nexus 9000 switches. And we've been used the modules for one and a half months without any problems so far. Cheers!

Delivery speed is very fast. I am satisfied with the item I ordered. I have always had a big demand for 40G transceivers. Previous partners often have problems with no inventory, or very slow delivery. But FS doesn't, I like to work with efficient people.

This is my first time shopping on FS.COM, mainly because I saw a very rich variety of products on the site., so I plan to try to buy it once. I bought two 40G QSFP+ transceivers that are very stable. A very satisfied shopping.

I met a compatibility problem is that the QSFP can't show DDM. But my sales is positive to help me solve the problem. She sent me 3pcs sample QSFP with different code for testing. And one of the QSFPs works well with DOM, then the return completed successfully. What matters is the attitude not the problem. Like this company, I have faith that they will have a good future.