Advanced Charging Technology - With USB Rechargeable 650mAh high capacity Lithium battery that lasts up to 10 hours. You can recharge the lights via a USB cable connected to any power output device, which is very convenient. Easy to Install - Easy to mount or remove with the equipped silicone straps that can be stretched up to 4.72 and fit most seat posts, handlebars, seat risers, backpacks, and helmets. Super Bright & 4 Modes Optional - Featured LED chips that provide you with maximum brightness and extra safety. The One-Touch switch with 4 lighting modes provides you good performance depending on your needs, including Full Brightness, Half Brightness, Fast Flashing, and Slow Flashing. Waterproof & Durable - Made of grade materials and with IPX4 waterproof feature, the led Headlight and Taillight can be used in snow, rain, storm and even underwater. Muti-functional - This is not only just a bike light set for cycling, hiking, camping, or any outdoor activity but also can be used as emergency flashlight in places where visibility and safety are concerned.