Featuresr with smart light sensor the brightness of this bike light will become stronger if the ambient light is darkr built in shock sensor the light will turn off in 3 minutes if you forget to turn off the light and then turns on automatically if you begin ridingr ultra wide 180 degree reflection angle with evenly distributed lighting ensures your night riding saferr convenient and fast usb charging charging time 15 25 hoursr power saving design 2 hours in strong light up to 6 h