Necklace Hanging Portable Car Oxygen Bar Negative Ion Air Purifier (Black) The air purifier with chain is portable to release negative ions to fresh your personal space, improving air quality. It can be used in your car, travel, public place or other places with poor air quality. Features: It will release over 6 million negative ions, removing pollutants from your personal space, removing most smoke, kitchen odors and even PM2.5 pollutants from the air. Comes with a necklace, it can be worn around the neck. Suitable for travel, public places or other places with poor air quality. Using advanced fans, the sound is very quiet during operation, it will not bother you when working or at rest. Easy to operate, just press the button for two seconds to enjoy the fresh air. USB charging port that can be charged for half an hour and used for about 24 hours to ensure fresh air. Specifications: Material: ABS Color: Black, White (optional) Input Voltage: DC5V Output Power: 0.1W  Frequency : 2KHZ Battery: 3.7V 200MAH Battery Charging Method: USB Pollutants Reduction Rate: Less than 96% Air Purifier Volume: 50m3 / h Item Size: 60 * 55 * 20mm / 2.36 * 2.17 * 0.79in Package Weight: 30g / 1.06ounces Package Size: 100 * 100 * 55mm / 3.94 * 3.94 * 2.17in Packing List: 1 * Purifier 1 * Chain 1 * Data Cable 1 * Instruction