Medela Calma Teat is a silicone teat suitable for use in Medela breast milk bottles. The Calma system is suitable for the mother looking for a solution to feed her baby with breast milk. Calm is the ideal teat for babies who are breastfed because it allows them to breastfeed, swallow and breathe as they have learned in their breasts. Whether you are breastfeeding or using the Calm teat, your baby has to create a vacuum for breast milk to flow. As soon as the baby pauses, the flow stops, just as in breastfeeding.