Aquaheat Stainless BottleInnobaby's Aquaheat is an on the go instant food & bottle warming solution for today's busy parents. It's simple to use as our warming system does not require a battery, electricity, or microwave to activate heat. Simply add water to the heat packs to activate heat anytime, anywhere, just when you need it. It's portable, lightweight, and simple to use. How does it work? no battery or electricity is required. Heat pack reacts with small amount of water