NUK First Choice Classic Pacifiers are accepted by 96% of babies* and feature a unique nipple that fits baby's palate for natural oral development. The asymmetrical nipple shape allows more room for a natural sucking motion, reduces pressure on teeth and jaws, and helps prevent teeth misalignment. Invented over 60 years ago by pediatric dentists and doctors, the NUK orthodontic pacifier is modeled after the natural shape of mom's nipple while breastfeeding. This makes for an easy transition from breast to pacifier and back. The heart-shaped shield fits perfectly under baby's nose for easier breathing and prevents irritation. All pacifiers are BPA free and dishwasher safe (top rack only).