Polypropylene Bottle made from material meant only for food contact application. These Bottles are 100% BPA free and are manufactured using machinery from Japan.Be sure to test temperature of feed before giving to infant. Ensure retaining cap is securely tightened but avoid over tightening. Always hold infant while feeding.Use only the correct liquid silicone rubber nipple as per your baby's age and feeding requirement. Only use Small Wonder L.S.R. nipples and accessories along with Small Wonder feeding bottles to ensure product performance. For better hygiene Small Wonder L.S.R. Nipples should be replaced every 3 months.