This 5oz Stainless Steel Baby Bottle from Klean Kanteen has all the safety of glass but is pretty much indestructible. Features a double-venting system to reduce colic and a slow-flow medical-grade silicone nipple to promote healthy breastfeeding. Includes inside and out measuring marks. Compatible with all Klean-Kanteen wide mouth caps. Cap is BPA-free polypropylene. Made in China by Klean Kanteen.