Spent more money thinking I would get a slightly better device. Was bitterly disappointed. I used it on three cables, the last one showed a bad pair 5 and no connection on pairs 4, 6 and 7. I thought I had a bad cable so I replaced it - ended up wasting time because of the tester was bad. I don't know how to file a warranty return as the Hobbes Industrial website says nothing about the warranty. I will never buy this brand again.