With the Mixie Baby Mixie 8oz Formula Mixing Baby Bottle the formula goes in the little compartment and the water goes in the bottle. At the first cry, just push the button, shake and blend. It's simple, yet really quite genius. On a flight, or in the middle of the night, the Mixie Baby Mixie 8oz Formula Mixing Baby Bottle has you covered. Because when baby wants a bottle, baby wants a bottle now.