Working on electrical stuff at home? Safety first! This Amtech voltage tester pen is a super handy tool. It's a screwdriver with a built-in voltage detector. You simply touch the tip to a wire, outlet, or terminal, and if there's AC voltage present (up to 240V), a light on the handle will glow. It's a non-contact way to check if a circuit is live before you start working on it – a potentially life-saving check. Model is L4100. Brand new. Essential for DIY electricians, handymen, or anyone who needs to do basic electrical troubleshooting. Remember, it's a tester, not a substitute for proper safety procedures and knowledge. Always assume a wire is live until you've proven it's not with a reliable tool like this.