The built-in rechargeable battery can be fully charged in just 1 hour and 30 minutes through Micro-USB - ideal when your riding is more time critical! Contrary to its size the COB-X (red) provides high luminosity with two flashing modes and one constant mode (lights flash red) Under flash mode the GUEE COB-X safety light provides up to 15 hours of light per charge! Features Bright and effective LED lights for improved safety 90 minutes fast charging provides up to 15 hours run time Can be mounted both horizontally &38; vertically ideal for use on a standard bike recumbent bike baby stroller walking stick and many more