I shopped some 10G modules and cables from FS before, which have been working perfectly in our data center so far. Recently, we wanted high-quality 40G optical transceivers to add some 40G links. So we purchased several Cisco QSFP-40G-SR4 compatible modules this time for our Cisco Nexus series switches. These 40G SR4 modules could split 40G to 4x10G signals, so we could reuse the modules with 10G products. Plus, we added some matched MTP® patch cables including #66234 and #66240. The products are all protected well in the packages. Plug-N-play, easy to handle. No compatibility issues. These QSFP+ modules work fine so far and the 40G network is stable. I will continue to monitor the modules' performances and come back with more useful feedback then.

Haven't bought any optical products here before. Someone recommended FS.COM on Reddit. After browsing their website, we decided to buy some 40G modules for a trial. The modules worked flawlessly on our Cisco Nexus series switches and passed our tests, featuring high performance and reliability. Pretty nice! Will place a complete order for our project.

Fast service, helpful advice, good price. Thank you FS!

Ordered these as a last-minute replacement for a project, they come in on time and work great, don't seem to get hot or anything like that.

Great price and fast shipping. I tested my fiber network after installing this module and the signal was well within specs. I will be ordering from FS frequently.

These transceivers work fantastic and I\'ve had no compatibility issues, even with multiple brands of switches and NICs. They feel very high quality and robust, run cool, and have performed well for everything I\'ve done.

This is the second time I purchased transceivers from them, because the last 10G modules and cables I got from them worked well in the telecom room. This time, I consider to buy some 40G modules to connect two Cisco N9K-C92160YC-X in a rack, the distance is about 15m. Before I told the salesman I already got some MTP® cables, she recommended using 40G QSFP+ AOC cables in my case. I have to say she is really considerate to provide more cost-saving solutions for me. She also kindly helped me place this order after I explained only these 40G modules are needed. The package comes with lots of protection for the transceivers. Worked right out of the box, just plug and play, with no compatibility issues. Till now haven't had any issues whatsoever with these modules, don't seem to get hot or anything like that. There are many more expensive transceivers out there, but these modules also work fine. No need for more expensive modules if your switch can use them.

We wanted high-quality 40G transceivers to connect the distribution layer switches for a reliable network with redundancy. And can do some 10G links for wired and wireless downlinks. We had searched a lot of vendors, finally, we chose FS for their overall strength.

First, they assured us that the 40G SR4 modules could split 40G to 4x 10G signals. So we can reuse the modules with 10G products.

Second, we were confused about the QSFP+ modules’ consumption value. Checked that the value of SFP+ module was approximately 1W. So one QSFP+ may be 4W, we thought. But actually, it was 1.5W. Wondered if there was something wrong. FS technical team explained that 1 QSFP+ consumption value was not equal to 4x SFP+ values, and 1.5W was the normal value of a QSFP+ SR4, and the team sent us the QSFP+ testing datasheet. We searched that the original Cisco 40G SR4 module’s value was 1.5 watts actually.

Plus, our company has no professionals so we needed some technical support, FS offered us remote support. I have followed FS Page on Twitter, and noticed that they offered on-site installation in Singapore. Looking forward to enjoying this service in London soon.

We also bought the matched fiber cables with the modules. All run great, transmissions are stable. Our network now is a powerful one with redundancy.

I googled FS on account of the recommendations on the forums. Then I placed the online order after browsing some nice reviews. It turns out FS IS a veritable vendor: the outlook of the QSFP-SR4-40G transceiver is quite neat (FYI: I particularly added a customized logo of our company); the product is also high-quality with reasonable price; fast shipping as it was promised—I received my package on the third day of my order. A 100% satisfying shopping experience!

Purchased 6 to use in a nexus 3172 switch QSFP+ ports, instantly recognized and available. Bandwidth and transfer speeds test exactly as expected. Worked flawlessly with no troubleshooting so far. I have bought 10G transceivers here in the past and they've always worked great. These are no exception. Price is fantastic. Highly recommended!