This is my first non contact tester, before i used a multimeter so this cuts the work by some, but most important it detects voltage through the wire, extremely useful tool for electrical work, i tested it on all sorts of circuits and it works great, the down side for me is when used in a panel box with multiple live wires there is no way to pinpoint one, i think the sensitivity is way to high for panel box work, so i still have to walk with my meter, but it works for most other circuits