Ethernet Cable Tester - RJ45 - Cat 5e
This is the iMBAPrice - RJ45 Network Cable Tester.
You can find this tool here on Amazon.
This is a pretty handy tool to have especially if you make your own ethernet cables. If you are making your own cables you are going to want to test them to be sure that you didn’t mess anything up. This is also really helpful if you have a large number of cables laying around and a certain percentage of them are bad (ex. in a datacenter). Even if you don’t run many cables, this is still a nice thing to have around.
This tool can be separated into two parts so that you can test a cable even after it has been run over a long distance. Just connect the tool on both ends.