The NUK pacifiers unique breast-like nipple is shaped to soothe baby just like mom. This makes for an easy transition from breast to pacifier and back. Invented over 60 years ago by pediatric dentists and doctors, NUKs unique orthodontic nipple shape helps promote healthy oral development. The NUK heart-shaped shield fits perfectly under babys nose for easier breathing and prevents irritation. NUK pacifiers glow in the dark, allowing parents and babies to easily find the pacifier at night if it falls out of the childs mouth. To activate the Glow in the Dark feature, expose the pacifier to light for two minutes until the puller glows green.