Comotomo Nipple Packs are replacements specifically designed for Comotomo Baby Bottles. Each pack comes with 2 silicone nipples designed to most closely mimic natural breastfeeding. Our naturally shaped, soft, silicone nipples are ideal for babies who have trouble transitioning from nursing to bottle feeding. Each replacement nipples also have two truly innovative vents that are built in to prevent colic, while totally eliminating leaking issues. ‰ÛÏTruly" Slow Flow (1 Hole) 0 3 months Medium Flow (2 Hole) 3 6 months Fast Flow (3 Hole) 6+ months Variable Flow (Y Cut) 6+ months (thicker fluids).