Ember Mug Lid

This lid serves serves 2 main functions (in no particular order)Extends in-use battery life by 2.4 timesPrevents the development of a (disgusting) skin / film from forming on the top of coffee with cream if the coffee isn't drunk fast enough This lid fits the 10 oz Ember mug, I'm unsure of the 12 oz mug. This is not a sippy lid, just a cap. The sloped interior of the lid is designed to encourage condensate to drip back into the mug. I would avoid using carbon fiber and glass reinforced filaments.