Review on TNP Ethernet Cable Splitter and Combiner for Enhanced Connectivity by Chris Brazington

They work as advertised but it's not clear they come in pairs because you need one on each end. In other words, here's how it's done: 1) Connect the two RJ45 ends of the first adapter to two Ethernet ports on the router or switch. 2) Connect the Ethernet cable to the first adapter. 3) Plug the remote Ethernet cable into the second adapter. 4) For example, connect two cameras to the ports of the second adapter. You now have two cameras using only one Ethernet line. Works great!