The Milwaukee REDLITHIUM® USB Charger charges the Milwaukee REDLITHIUM® USB Battery. A 2.1A charge rate delivers up-to 3X faster charge time. Get 50% of a charge in under 30 minutes, 80% in under one hour and a full charge in 2 hours so you can get back to work fast. Conveniently charge REDLITHIUM™ USB Batteries via Micro-USB Cable from a wall plug or USB power source. The REDLITHIUM® USB Charger is covered under a 2 year warranty.