UV light destroys germs' ability to reproduce and make you sick; The SteriPEN destroys over 99.9% of bacteria, viruses, and protozoa;Battery Life: Up to 50 treatments per charge and 300 charge discharge cycles; This is equivalent to 15,000 liters;Simple OLED display shows everything you need to know - treatment, lamp, and battery status; USB rechargeable from a computer, wall, or solar panel;Water Quality Association: SteriPEN tested and certified by WQA against US EPA Microbiological Water Purifier Standard