Philips AVENT SCF675/01 Natural 4 Ounce Glass Bottle sleeve is the ideal way to protect your glass feeding bottles and it also helps to keep liquids either warm or cool. With a convenient opening, you can easily see how much milk is fed and see the bottle's feeding scale. It's machine washable and the fabric is certified by the OEKO-TEX Standard, which is an independent testing and certification system for textile raw materials, production and end products.