From the Pura website:
More About This Product
Pura is the first and only juvenile bottle provider to ship its bottles with a 100% plastic-free silicone travel nipple/spout travel cover. This revolutionary design not only eliminates plastic components but provides much improved functionality as it does not "pop" off the bottle when jostled about in a bag. Also in accordance with re-purposing philosophy, the travel caver can also be used as a plastic-free snack cup for toddlers in a stroller, pram or car seat!
- Covers & protects the nipple of spout while on the go
- Secure fit prevents leaking — all other nipple covers are plastic and they easily fall off in one's bag. Our design is secure even when jostled about
- Tinted opaque blue now
- As with all products in the Kiki line the travel cover is 100% plastic-free
- Meets all FDA, CPSC, EN14350, European Commission 10/2011, German LFGB regulations and/or guidelines