We bought this product for our IT shop after watching a video on Youtube. We used it for a project and tested ethernet network cables, it worked fine. On the second project a month later, we kept getting false alarms from some cable clamps. We checked with another cable tester and the cables were fine. We picked up a cable from storage that appeared to be working and had bugs. We tried contacting the company via phone and email but there was no response. In the end we just gave up and bought a replacement from another company.