This Special Slow Flow Feeding Bottle 180 mL has a patented anti-colic pouch system, which retracts like breast glands when Baby suckles. This prevents the formation of air bubbles, which prevents baby's gas colic, reflux and oxidation of milk. At the special breastfeeding rate, the bottle lets more or less milk through depending on the strength of baby's suckling. The teat mimics the breast and is accepted by newborns and premature babies. The bottle is designed for alternating between bottle-feeding and breastfeeding. It is dishwasher safe.