500 ml double walled vacuum water bottle with UV-C sterilizer. This UV kills up to 99.9% of the bacteria in the drink inside the bottle. You can choose to do a quick clean in 3 min sterilization or a complete clean 5 minute sterilization. For protection, the UV-C light automatically switches off once the lid leaves the bottle. With a 400 mAh battery, the UV-C light can work for 2.5 hours or 50 regular sterilizations. The bottle keeps a drink hot for 12 hours and cold 24 hours.