The Haakaa Glass Baby Bottle is ergonomically designed to provide the most natural feeding experience for your baby. The orthodontic anti-colic nipple thumb-shaped teat included mimics the shape of a mother’s nipple during breastfeeding, and the offset position allows you to feed your baby without completely inverting the bottle. The glass bottles are made from temperature-resistant borosilicate glass, which makes them 100% safe to freeze or heat and perfect for storing expressed breast milk. Every second, an estimated 1,500 plastic bottles either end up as waste in landfills or are thrown into the ocean, with a huge portion of these being plastic baby bottles. Haakaa has created glass baby bottles to reduce plastic waste in our environment and move towards a cleaner and greener world. Replacement or different size teats can be found here: Haakaa Gen. 3 Silicone Orthodontic Teat - 2pk Haakaa Gen 3 Anti-Colic Nipple - 2pk Please note the original 90ml and 160ml versions are being replaced with 120ml and 180ml sizes. The bottles are the exact same size except the measurements have been extended.