Reduces colic with vented nipple design for less air. Made of soft, clear and durable silicone. Simple solutions for your baby. BPA free. First Essentials nipples are specially designed for your baby's feeding comfort at every stage of development. Made of soft, clear and durable silicone. Vent holes and ribs ensure smooth flow and help prevent nipple collapse. Fits most standard, reusable bottles. Assembled in USA.