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. Absolutely a perfect add-on for night safety cycling. Features: Ultra light and ultra thin, easy to attach to a backpack without adding extra burden. 4 Led signals, reminding passengers and drivers to keep a safe distance. Wireless control, mounting it on handle bar, free your hands, safe and convenient. Built-in 500mAh rechargeable lithium battery, easy to recharges from your computer or any device with USB port. 12-150 hours of continuous work after 2.5 hours full charging. Adjustable elastic straps to fit your backpack perfectly. Perfect choice for running, cycling, mountaineering, hiking, fishing, cross-country and other outdoor activities. 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