Hegen's slow flow teats are designed to encourage seamless breast and bottle feeding, minimising nipple confusion for your baby. our velvety soft elliptical shaped teat closely mimics a mother's lactating breast while the off-centre teat design promotes upright feeding; similar to a position in which babies are nursed to reduce the risk of milk back-flow and the resulting mid-ear complication and colic. The built-in anti-colic air vent reduces unwated air intake and prevents bubbling of milk, saving precious nutrients from oxidation. (teats are marked with "1/2/3/4" embossing to indicate slow flow/medium flow/fast flow/thick feed respectively)