The Philips Avent Natural Glass Bottle is designed for a natural feeding experience. The ergonomic glass bottle is easy to hold and heat. The nipple features soft, textured petals and a natural shape to promote a deep latch and comfortable feeding. An anti-colic valve is designed to keep air out of baby's tummy, reducing colic and fussiness. This bottle is made of high-quality borosilicate glass, which is heat and shock resistant.