The most natural way to bottle feed; Wide, breast shaped silicone nipple promotes natural latch on, so its easy to combine with breastfeeding Advanced anti colic system is directly integrated into the nipple with no extra hard to clean parts Made of premium quality, pharmacy grade borosilicate glass; Heat and thermal shock resistant Wide neck opening for easy filling and cleaning Compatible with all Philips Avent Natural nipples; These bottles include 0Month+ Newborn flow nipple BPA Free