Product Description Features A unique nipple with an air valve at the base, enabling a venting process, thus providing a smoother flow of liquid, thereby preventing against nipple collapse, colic, and spit up, burping, and gas. Simulates breast feeding thus making it easier to alternate between breast feeding and bottle feeding. Easy latch on. Made from high quality medical grade silicone. Volatile and nitrosamine safe. Odorless, tasteless, and guaranteed not to perish. Age limit 6m+