Pigeon KPP Wide Neck Plastic Bottle is designed to facilitate and promote a correct latch on, the natural peristaltic movement while sucking, and the effortless and smooth swallowing of milk. This bottle makes it easy for the baby and the mum to switch from breastfeeding to bottle-feeding. PPSU stands for Polyphenylsulfone, the safest & most durable material for baby bottles. PPSU is a medical-grade plastic that's naturally honey-toned and incredibly hard-wearing. Again, it's a very safe plastic and is the 'gold standard' when it comes to baby bottles.