Simply press the button on the lid and UV light will purify your water in less than 15 mins so that the interior remains free from contamination. The UV light and battery are incorporated in the lid, and the USB battery can have a charged life of up to 2 weeks. This stainless steel, double walled, vacuum insulated bottle can be filled and with water and purified anywhere. It can keep liquids hot up to 12 hours and cold up to 24 hours.