Medela Calma 250ml Bottle for Breast Milk is a feeding solution specially designed for breast milk. To design the Calma teat, Medela has studied what happens in baby's mouth when breastfeeding. Milk does not flow automatically. During breastfeeding, your baby can pause and breathe. Calma cones in one size ! This is suitable for the entire duration of breastfeeding. Pioneered to benefit the mother and baby's unique breastfeeding bond. Calma teats are compatible with all reusable Medela Breast milk bottles. Contains : One 250ml bottle with Calma teat and 2 lids to store breast milk.