I've done half a dozen jobs with this tool and about halfway through the second job I noticed that some of my remotes were causing false negative problems. including one that always failed on every line. I reworked countless endings to pass the tester. I turned to Klein for help. weeks pass. No Answer. Now the clients are starting to connect using the cables I built and I've found that more than half of them still don't work despite the tester saying they pass. And lest you think I mixed up my fake messages with fake ones, this doesn't always happen with the same remote controls. In other words, right now I can't trust the responses from my remotes. One of my customers provided me with his own tester to show me the errors. To add insult to injury, we isolated the wiring error because the Klein crimping tool I bought (Klein Tools VDV226-110 Ratcheting Modular Cable Crimper) isn't crimping the first two pairs properly. These two Klein products together have left me very embarrassed in front of several clients, not to mention that I spent all day today reworking all the ends I left in a large warehouse with my "crappy" old tools and built my customer's precision tester. Then I have to take the shameful walk around other jobs to redo all my work. Costs me more than time and material; worth my reputation which is very hard to earn for a woman in IT. It's sad because the concept of this tool sounds so great and if it works properly then it would really save me a lot of time if it worked for a woman. So incredibly disappointed in Klein at the moment!