Warning: 1) For the first use, please read the quick guide and install the batteries correctly according to the marks. 2)Please remove the batteries at least a month and visually inspect the inside of the flashlights for signs of corrosion. 3) If your flashlights are used infrequently, e.g., once a month or less, it is recommend to remove the batteries and store them separately.This helps guard against corrosion and may also prolong batteries life.