Our baby bottles are made of the highest quality, thermal shock resistant borosilicate glass. This allows our bottles to transition safely from freezer to boiling water. The silicone sleeves provide a good gripping surface for little hands and help protect against the occasional drop. Includes 9-ounce (250 ml) bottle with Stage 2 (3-6 mos) nipple. Care and use - Before first use, place in dishwasher or in boiling water for 3 minutes. This is to ensure hygiene. Immediately after use, disassemble individual top components (e.g. nipple from top or valve from cap). All parts are dishwasher safe (top rack only). To wash by hand: wash separately in hot, soapy water and rinse thoroughly. Bottle and sleeve may be placed in the dishwasher or boiled without removal of the sleeve. If you wish to remove the sleeve, it comes off best in warm, soapy water. To allow venting and prevent nipple/valve collapse, do not over-tighten screw top