Ember Mug 2 Designed for home or office, the Ember Mug 2 does more than simply keep your coffee hot. Our smart mug allows you to set an exact drinking temperature, so your coffee is never too hot, or too cold. Ember then maintains your chosen temperature for up to 1.5 hours with the Ember Mug 2, 10 oz and up to 80 minutes with the Ember Mug 2, 14 oz - so your hot beverage stays perfect. Ember Mug 2 is safe to hand wash and submersible up to 1 meter in water.