The Bebek Collection offers a wide base nipple for easierlatch and transition. The silicone Proflow nipple rapidly vents releasing airbubbles into the bottle not baby s tummy significantly reducing gas colicand fussiness. Bebek nipples are expertly designed not to leak and to be usedon all 5 ounce and 8 ounce Bebek bottles. The simple one piece nipple andvent means no extra parts to clean or lose. Medium Flow nipples are designedfor babies 3 6 months. Enjoy the bonding time that feeding provides. From theManufacturer The Bebek Collection offers a wide-base nipple for easier latchand transition. The silicone Proflow nipple rapidly vents releasing airbubbles into the bottle not baby s tummy significantly reducing gas colicand fussiness. Bebek nipples are expertly designed not to leak and to be usedon all 5oz and 8oz Bebek bottles. The simple one-piece nipple and vent meansno extra parts to clean or lose. Medium Flow nipples are designed for babies3-6 months. Enjoy the bonding time that feeding provides.