Who said you have to throw your bottles away when your baby is done with nipples! Now you can easily convert your Chiller's inner chamber or any narrow-neck bottle to a sippy cup with our beautiful sip-top lid! Also fits the Ceres Chill Cup with the connector as a sip-top lid. This special, patent-pending attachment is convenient and easy to use, so you can keep your little one fed or hydrated wherever you're headed. To convert any narrow-neck bottle into a sippy cup, just swap out the nipple and attach the sip top lid to allow your growing baby to gradually develop from infant nipples to toddler sippy cups. Food-safe, flexible silicone. - Made out of 100% soft and durable silicone that is gentle on teeth and gums. - Comes as a set of two (2) so you always have one when you need it. - Easy to clean — just toss it in the top rack of the dishwasher!