Einfach Twin Lids Double Wall Insulated Glass Water Bottle with Detachable Tea Infuser Healthy and Environmental Material: made of high borosilicate glass (also known as hard glass) which can keep hot for 3 hours and two stainless steel lids. The grade of the glass is oak crystal, lead free, low inflation, high heat resistant, high strength, hardness and high chemical stability. No worry of BPA or plastic! Double walled design: keeps your beverages hot or cold while protecting your hand from hot temperatures. Transparent glass design: allows you to enjoy the visual experience of brewing loose-leaf teas, fruit tea or juice. Leak proof, no spill: gets the glass part screw into stainless steel lid, no gap, secure and tight Easy to Clean: contains two lids and two open ends which allows for simple cleaning and air flow for natural drying. No musty odors.