Test functionality and wiring of USB ports. Make the perfect impulse and promo item. Designed for home, office and auto, these testers feature hi-impact ABS housings with 250 pound crush rating and the ability to withstand a drop of up to 10 ft. Increases productivity on any job it faces. These compact testers can fit can fit in shirt pocket or tool pouch, making it easy and convenient to use. Test for proper wiring and polarity. Features: Easy to use and understand, Pocket clip, High impact housing.