Liquid Silicone Rubber Nipple is especially designed to help prevent colic. The Nipple is made using quality grade silicone rubber to ensure hygienic usage and is also delicate to the baby. The Silicone Rubber Nipple is provided with an air valve in the base of the teat, which allows air to flow back into the bottle, ensuring a steady flow of milk. The Liquid Silicone Rubber Nipple is bacteria free and transparent.