I've gone thru 3 different Voltage Ticks lately because the others were completely useless. This one is only partially useless. The problem is that most will light up even on low voltage DC current, which does not suit my purpose. As a home inspector I need to verify if it's high voltage 110v AC or Low Voltage like 5-20v DC. Low voltage can be exposed but high can't. This one sometimes will light up on low voltage but mostly not. Don't know what has changed lately but I don't recall having this problem years ago.