If you have ever wondered just what the voltage at a USB port is, or just how many amps, or fractions thereof, are passing through, this little device is a handy tool.
Product Name: Xtar VI01 USB Current/voltage detector
Review of product: (http://www.candlepowerforums.com/vb/showthread.php?382697)
Detector only @ Amazon (http://smile.amazon.com/XTAR-Decision-Display-Detector-Current/dp/B012C3T9OA/ref=sr_1_3?ie=UTF8&qid=1439773487&sr=8-3&keywords=Xtar+VI01+%22USB+Detector&refinements=p_85%3A2470955011)
Detector and single cell charger (Li-ion) (http://smile.amazon.com/Bundle-Battery-Charger-Detector-Batteries/dp/B00WU3KIRU/ref=sr_1_2?ie=UTF8&qid=1439773487&sr=8-2&keywords=Xtar+VI01+%22USB+Detector&refinements=p_85%3A2470955011)
Detector and single cell charger, plus one 18650 Li-ion cell (http://smile.amazon.com/XTAR-one-slot-Charger-Constant-Detector/dp/B00X9YRKK2/ref=sr_1_4?&ie=UTF8&qid=1439773017&sr=8-4&keywords=Xtar+VI01+%22USB+Detector&refinements=p_85:2470955011)