Attach this clip to your backpack to increase visibility and safety at night. The LED lights can respond to the signal received from the remote controller, reminding passengers and drivers keep distance from you. Built-in 500mAh rechargeable battery. It can work 12-15 hours of continuous work after 2.5 hours full charging. a perfect add-on for night safety cycling. Specifications: Material: Nylon polyester Color: Yellow / Gray ( optional ) Working Time: 12 - 15 hours Charging Time: 3 hours Battery: 4.2V, 500mAh Bag Size: 24.5 * 24.5 cm / 9.6 * 9.6 in Bag Weight: 148 g / 5.2 oz Pacakage Weight: 194 g / 6.8 oz Package List: 1* Backpack 1 * Wireless Controller 1 * Controller Mounting Base 4 * Zip Ties 1 * Manual