Feature: 1. Wide applicability, can be installed on the front or rear fork of bicycles with a diameter between 15-41 mm. 2. Compact size, easy to install. 3. Energy conserving and environmentally friendly. 4. Generates power at speeds of 5-30 km/h, producing 100-1000mAh of electric power. 5. Dual USB output interface; 4-style single light indicates battery level. Specification: Item Name: Chain Type Bicycle Dynamo Size: 80 x 50 x 80mm Battery Capacity: 1000mAh Standby Current: Output power: 5V/1A Working Temperature: -10C to 40C Includes: 1 x Bicycle Generator Shipping Information: All items will be shipped within 3 business days after payment is received. Delivery typically takes 8-12 days. Exact delivery time may vary depending on location. Customer Service: If you have any questions, please . We will respond within 24 hours. Thank you for your support and we hope you enjoy your shopping experience.