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.

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!

I ordered two QSFP-SR4-40G transceivers and one MTP cable for connecting two Cisco Nexus 3000 series switches. To be honest, I was a little worried about the compatibility issue, but it turned out to be unnecessary. The transceivers worked perfectly with our switches. And we've been using the QSFP-SR4-40G modules over the past fortnight without finding out any packet errors or interface issues. Kudos to your superb product and your first-class services! I will definitely shop here if needed!

We have optimized our network recently, wanted to buy some transceivers for our new Cisco and Arista switches. But we had a budget. Luckily, found FS. Before ordering, we were concerned about the module’s compatibility. Because we bought some modules from other providers, but they were not compatible with our hardware. So we first applied for a compatibility testing sheet at FS. Nice experience. We ordered some Cisco and Arista compatible modules after receiving the testing report. The modules have been worked for a time. No packet loss, and transmissions are stable. Our IT teams are satisfied with them. Their services are really good. We wanted to get the products as soon as possible. FS provided us the same day shipping. Surprised that they had a warehouse in America, not far from our company, so we received the modules very quickly. My items are well packaged, and no damages appeared during the delivery. FS deserves 5 stars.

Their technical team is great and really helped me a lot. I was planning to upgrade my 10G network. It seems 25G is very popular these days, but I didn’t know if it worked for me considering the future growth for 40G or even 100G. I am not a network engineer with much experience. Diving on the Internet for info many days, I happened to find FS. So I sent an e-mail to them with my problems to have a try. That was amazing! They replied with an entire solution based on my network, which proves a 40G network works best for me. They even considered the cost in the solution and helped me to control it at the optimal level. With such a professional team, I bought all the 40G products they had for my 40G network without hesitate. Thx FS technical team. If there is any need in the future, I’m sure I will choose FS again.

Our lab needed an upgrade to 40G. So bought the 40GBASE-SR4, MMF, 850nm models for our Jniuper QFX5100-24Q switches. We have used some compatible transceivers from other providers, not very stable. Sometimes, the modules caused the switches to restart. So we had to buy new ones. When we received the FS items, we did a test, they were actually compatible with our hardware. And excited to experience the same functions as the Juniper's own transceivers at a more economical cost. Plugged right into our switches, no technical issue. Great value for the money and great compatibility with our hardware. Besides, FS services are good. Asked the after-sales service, they told me the product supported a 5-year warranty, responded very quickly. Good experience.

Bought four for my Cisco switches (N9K-C9396PX & Nexus 92160YC-X). Used for almost two months, they work well on my switches, no technical issues with the products have been reported.

Customized several Cisco compatible QSFP+ modules. Received on time, and well packaged. Now, we have utilized our MTP cables to push 40G to our Cisco switch. Links have been up for about 3 weeks with no problems. Cost-effective products, will come again.

We have been using the QSFP-SR4-40G for the past week. It has worked perfectly. As expected, there are no packet errors or interface issues. When we plug the adapter into the port, the Cisco switch recognizes the adapter and allows us to configure the interface settings as expected. The price of this 40G transceiver is also very competitive, I am very satisfied.