Recommended for babies with stronger sucking ability who are already accustomed to bottle feeding. This product features a glass bottle with a plastic screw-on cap. Please ensure the cap is properly aligned and fully tightened before each use. While designed to support a natural feeding experience, nipple acceptance varies by baby. This is a glass bottle. Avoid drops, impacts, or sudden temperature changes. When using a bottle warmer, follow instructions carefully and avoid prolonged overheating. Discontinue use immediately if any cracks or damage are observed. Newborns or preterm babies may require a slower-flow nipple (Premie or Size 1), sold separately. Philips Avent Glass Natural bottle with the Natural Response nipple lets baby control the pace of the milk, like they do when breastfeeding. This Natural Philips Avent bottle is made of premium quality borosilicate glass, a BPA free material. It is heat and thermal shock resistant, so it can be safely stored in the fridge, warmed and