Though introduced last year, Mixie's formula-mixing baby bottles are expanding into the mainstream this year with broader distribution throughout the country. The bottle is divided into two compartments — one for the water and the other for the powdered formula. Start the day off by filling the chambers with the necessary amounts of formula and water. Then, once baby's feeding time arrives, simply push a button on the bottom of the bottle and watch as the formula is dispersed into the water. Sure, the model has a few more pieces than the average bottle, but that's the price of convenience, right?