Tigra BikeCharge Dynamo & Bicycle USB Charger Bike-mountable generator uses riders pedal power to charge almost any device. Requires easy DIY installation, fits most standard wheel hubs. Includes integrated USB 2.0 port, 1000 mAh Battery, and F/R LED lights with 3 lighting modes. Quiet and virtually drag-free, compatible with any type of USB-chargeable device. Scroll down to Description to see fitting requirements and FAQs.