Meet the world's first temperature-controlled mug, designed to keep coffee and other hot beverages at your ideal sipping temperature. Adjust the heat with Ember's mobile app – or opt for the handy preset of 135°F. The smart mug's integral battery maintains your chosen temperature for 80–90 minutes (depending on mug size). For all-day use, simply keep your mug on the charging coaster. I received this as a gift but did not use it. I believe this is the first generation. 10 ounce size