Run full testing on them to make sure there were no performance issues on Mikrotik CRS326-24S 2Q RM switch. Everything has been working flawlessly.

These modules worked well in my N9K-X9736C-FX line card for the N9K-C9504. The price is also great. I can't find any reason to go anywhere else.

I’ve looked for many venders who could offer the 40G 2KM QSFP+ transceiver. FS was on my select lists. By contrast, we finally opted for FS because they gained many positive reviews in my business field and the transceivers supported maintenance within 5 years. All in all, QSFP+ transceivers are nice and competent.

Thought both #48724 and #36172 could meet my 1km link. I contacted the AM and asked which item was better for me. The guy explained that the module #36172 could only work with SMF, while #48724 supported SMF and MMF. So I chose #36172 coz our existing fiber was SMF.

Plug the module into our Juniper device, it transmits data to our controlling room without any issues. And I’m impressed by the friendly and helpful AM. My need has been effectively and swiftly taken care of.

Purchased 2 for QSFP+ ports on our Juniper EX4650. Worked flawlessly with no troubleshooting.

Bought 10G SFP SR transceivers for our Juniper devices before. They worked great, so came here again for Cisco compatible 40G modules.
We searched on FS website first, and found both Cisco compatible 40G IR4 and 40G LX4 modules met our 1.6km transmission demand. The sales asked us the details of our network, and explained that 40G IR4 only worked with SMF cables, 40G LX4 could work with SMF and MMF. He recommended 40G IR4 models, because he thought the MMF cables couldn’t meet our long-distance link demand. So we didn’t need to cost more for the 40G LX4 modules.
They delivered the modules quickly. The items were well packaged in a box when we received them. All could work with our switch.

We needed 6 40G modules for about 1.5km link. We sent our modules’ requirements (like RX&TX power, RX sensitivity) to FS. They recommended these 40G IR4 modules, and some SMF cables. We checked the modules’ datasheet, they met our requirements, and some figures seemed better than we expected.
When we talked with the sales, we knew FS had a branch office in Melbourne, not far from us. So we decided to drive to their office, and pick up the items in store. The staff were glad that we came. They helped us check the quantities of the items and confirmed their appearances had no breakages. Then, the staff packaged all the products for us.
We install the modules and fibers, no packets dropped. 10/10 recommend.

Bought six these 40G IR4 modules. Working pretty well on my Cisco N9K-C9372PX and WS-C3850-48XS switches. Their application portfolio for IR4 on their product page is very considerate, happened to fit our network needs. So together with these modules, we also bought their FHD fiber adapters panel and D-ring panels, very convenient.

Needed to buy different 40G module types (IR4/CSR4/ER4/LR4/PIR4/PLR4/LX4) to work on HW switches. This was the first time to buy FS modules, so I worried their modules couldn’t work with our devices. Knowing my concern, they sent me test reports at once for those modules’ work performance on the same HW switches we have. I was shocked by their quick response. Sure, everything went smoothly. Their module tested to work with my devices very well. Nice service. We ordered all the 40G modules at FS without a doubt.