Yes, there is only ONE Calma size! Calma is designed to adjust to your babys suction strength as your baby grows, so you do not need to purchase different nipples for different stages. The length, shape and flow of the nipple was determined by clinical research and is suitable for the full-term babies. Don`t be fooled by Calmas opening! The opening of Calma is not indicative of the size of the milk flow. The milk flows through a very small hole inside the Calma. The flow speed is dictated by your baby: slow flow for the small baby to faster flow as your baby grows and gains sucking power. Calma helps avoid gassiness as it is vented through our unique air-control system.

• Your baby can drink, pause, and breathe in a natural rhythm, remaining calm and settled.
• Your baby needs to create a vacuum to start the milk flow.
• One size and shape fits all
• Safe drinking the baby does not swallow air during the feed
• BPA free and Swiss made safe for you and your baby