4000 mAh large-capacity battery. It can not only provide a long battery life of 4-8 hours for the Bike light can also charge your phone when the mobile phone is run out of electric .Our bike light is different from traditional bike lights ,which is the latest upgraded 4-in-1 function With mobile power, bicycle horn, bicycle light and mobile phone holder. Satisfy your different demands at the same time. We use IPX6 waterproof technology so that the bicycle lights can be used normally in heavy rain. when you rides in different weathers, you can still clearly see the road and passing vehicles(such as rainy/foggy/snowy), away from danger .The bicycle light has 3 light modes with different brightness. The horn with 5 sound modes is equipped with a USB key switch