Original orthodontic nipple. Helps reduce colic & promotes healthy oral development. Simulates & supports breastfeeding. Compatible with Nuk Wide-Neck Nipples & Nuk Breast Pumps. Brand trusted by moms for over 50 yrs. Nuk Air System. BPA free. Flat Area: Reinforces correct tongue positioning. Asymmetrical Widening: Encourages movement for correct jaw positioning. Hole Against Palate: Allows milk to mix with baby's saliva facilitating better digestion. Nuk Air System: Vent helps reduce colic. Extra-Wide Base: Mimics the shape of mother's breast. Special Design Helps Reduce Colic: The Nuk Air System vents the bottle, preventing vacuum build up - this allows baby to drink continuously, swallowing liquid instead of air. Available fin slow, medium & fast flow. Promotes Healthy Oral Development: Is the same orthodontic shape as Nuk pacifiers, designed to fit baby's oral cavity. Simulates & Supports Breastfeeding: The nipple is shaped like mother's breast during feeding. Supports switching between breast & bottle. Instructions for use & care are enclosed. Fashion meets function. Assembled in USA with parts made in USA and Germany.