This waterproof backpack is equipped with reflective strips and LED lights which will respond to signal received from remote controller, reminding passengers and drivers keep distance from you. Built-in 500mAh rechargeable battery. It can work 20 hours of continuous work after 2 hours full charging. Absolutely a perfect add-on for night safety cycling. Features: 4 Led signals, reminding passengers and drivers to keep a safe distance.? One spacious main pocket, two front zipper pockets and one inner elastic pocket holds your essentials securely. Wireless control, mounting it on handle bar, free your hands, safe and convenient. Padded back with mesh panels enhances breathability and comfort. Fully adjustable shoulder and waist straps for a custom fit. Survival whistle on the chest bag can be used in urgent needs. Built-in 500mAh rechargeable lithium battery, easy to recharges from your computer or any device with USB port. 20 hours of continuous work after 2 hours full charging. Perfect choice for running, cycling, mountaineering, hiking, fishing, ?cross-country and other outdoor activities.? Specifications: Material: Nylon + PC + ABS Color: Gray / Yellow & gray ( optional ) Working Time: 20 h Charging Time: 2 hours Battery: 3.7V, 500mAh Bag Size: 44 * 33 cm / 17.3 * 13.0 in Package Size: 41 * 32 cm / 16.1 * 12.6 in Package Weight: 458 g / 16.2 oz Package List:? 1* Bag 1 * Wireless Controller 4 * Zip Ties 1 * Manual