There was some mix up with the item I received in my original order but the seller rectified the issue immediately. I am very satisfied with the overall service. The Z-axis sensor works well and the tests I've run so far show it's reliably repeatable. I don't have an automatic tool changer. This allowed me to greatly simplify the process of changing tools and eliminate a huge source of errors when changing tools. All in all it's worth it. Note. I originally bought it for use on a Mach3 4x4 CNC router. I have since switched to UCCNC and am very happy with the move. That Z-axis sensor worked great on both. Actually even better on UCCNC since I have more sensor inputs.