Although It truly is plastic, it works with equally chilly and very hot beverages (up to 212 degrees Fahrenheit) and is safe to clean in your dishwasher (major rack only, remember to). It is available in a range of sizes and colours and the company even makes a sippy cup https://alkaline-refrigerator-wat76543.articlesblogger.com/40185304/what-does-high-alkaline-water-delivery-mean