Designed exclusively for breastmilk feeding, the Calma draws upon new research in infant behavior that makes switching baby from bottle to breast a whole lot easier. With its flow control valve feature, the bottle is specially designed to mimic breastfeeding, so that milk will only flow if your baby works to create a vacuum to remove the milk. (This in turn improves baby’s sucking power and ability to transition back to the breast.) It also features no-drip technology to prevent spilling — even when the bottle’s turned upside down — and a vented nipple to cut down on gassiness.