Modes include HIGH STEADY, MEDIUM STEADY, LOW STEADY, DAYLITE PULSE, NITELITE PULSE and ECONOMIC FLASH. FULLY USB RECHARGEABLE - No batteries to buy or replace. Run time up to 24 HOURS. Side illumination ports allow cyclist to be seen when riding across traffic lanes. Memory Function-Light turns on at the last mode it was turned off. Power saving function- 10% power or less, lights will automatically switch to lowest lumen output. Built in battery indicator- Red illumination = lower than 25%, Green = fully charged