Review on QSFPTEK 10G SFP RJ45 Module, 10Gbe Mini-GBIC SFP+ to RJ45 Module - 10GBASE-T Copper Transceiver for Ubiquiti UF-RJ45-10G, Netgear AXM765, Supermicro, Unifi - Up to 30m by Kenny Shaver

The name/description of this item is misleading. It says that the device will operate at 5G/2.5G/1G speeds in addition to 10G. HOWEVER (and I noticed this), the SFP port on your switch MUST support 10G before the module downgrades it to lower speeds. This is not specifically mentioned. The description sounds like you can use it directly on a 5G, 2.5G or 1G port, which does NOT work. I tried using two of these to connect a Cisco SG500-52P switch to a Cisco SG500-28P switch. Use of 5G SFP ports on each device. It did not work. The connection/activity indicators didn't even come on let alone flicker and it's obvious that no connection was made. I'm pretty sure they will work beautifully if you use them on a 10G port. However, if your switch doesn't already have 10G ports, they won't work for you. Two stars because the description should be clearer.