The Medela Calma Teat is a silicone teat suitable for use with Medela breast milk bottles. The Calma system is intended for mothers looking for a solution to feed their baby with breast milk. Calma is the ideal teat for babies who are being breastfed, as it allows them to suck, swallow, and breathe as they learned at the breast. Whether you are breastfeeding or using the Calma teat, the baby needs to create a vacuum for the breast milk to flow. Once the baby takes a pause, the flow stops, just like during breastfeeding.