Durable USB Rechargeable Battery - Built-in 650mAh lithium battery makes these LED bike lights super bright in the dark. Fully charged in 3 hours and lasts for over 6 hours, so you avoid unnecessary battery changes forever. They can be charged with any device with USB ports (PC/ portable charger/ wall charger/etc) and have overcharge protection. Absolutely the best USB bike lights for cycling enthusiasts! \n Four Light Mode Options -- Both the white front light and the red tail light have 4 light modes: Constant full brightness / Constant half brightness / Flashing flash / Stroboscopic. By simply clicking the button, you can switch modes as you like. Light up the road in front of your bike with a bright headlight and alert riders approaching from behind with the bike's LED tail light, giving you 360 degree protection. \n Installs securely -- Advanced and flexible silicone mounting straps provide great security and holds the USB rechargeable bike light set tight enough to prevent it from falling off even on rough roads. Detach and attach them easily without any tools. Fits all types of bikes such as children's bikes/ racing bikes. Package includes 2 straps + 2 replacement straps. \n Waterproof & lightweight -- Fully enclosed design to protect the bicycle light set from rainy days, even the USB port is fully covered, making it convenient to use in all weather conditions. The light and robust shell guarantees stable performance, which is very important when cycling in difficult terrain.