The Medela Calma + bottle ensures that your little one drinks just like at the breast. The Calma is based on a baby's natural sucking rhythm. Babies control the flow of milk by moving the tongue up and down and have to create a vacuum with the Calma itself to allow the milk to flow. This makes it easy to combine breastfeeding and bottle feeds. The Medela Calma comes with a 250 ml bottle. Suitable from 0 months. Color: transparent / yellow. BPA free