Review on Neoteck Voltage Tester/Non Contact Voltage Tester 12-1000V/48-1000V Adjustable Sensitivity AC Voltage Detector Tester Pen Live/Null Wire Tester With LCD Display Buzzer Alarm Wire Breakpoint Finder by James Morrow

I originally bought this to troubleshoot Christmas tree lights, for which it does not work well. When it is brought near a strand of light it sounds off and lights up. You can not analyze just one light. It is too sensitive.What it does well; if you want to know if an outlet has power just touch the outside of an AC outlet. It can tell the difference between the hot and neutral. Light and sounds on the hot, no reaction on the neutral.I also bought the Fluke 1AC-A1-II, 90-1000V VoltAlert Non-Contact Voltage Tester. The Fluke works perfectly on tree lights. Also on a two conductor extension cord, it can tell the difference between the hot and neutral side of the wire. However, it will not sense voltage on the outside of a receptacle.