【No Need to Refill Filter】: High concentration of negative ions can quickly kill all kinds of bacteria and germs and make your car with natural oxygen. Anion in air is like vitamin in food, which can facilitate body growth and disease prevention. In addition, it is unnecessary to change HEPA Filter, thus to avoids lasting cost【Dual USB Ports】: One USB port for inputting power to purifier and the other for charging cell phones or other electronic devices【Portable & Minimal Design】: The size is suitable for most car cup holder. Additionally, the aluminum alloy housing case and CD texture panel make it look more high-grade and unique【Ultra quiet】: The operating noise is less than 27dB (The sound of bedroom or desert night is 30dB). Which makes you feel comfortable during you drive and sleep