Made of Glass, Bamboo and Silicone. Stain-free, clean tasting, no plastic odors or taste by a natural bamboo straw. Colorful silicone sleeves provide a no-slip grip and make it easy for kids and guests to identify their own glasses. Protective silicone sleeves make the glass perfect for outdoor use as it will not sweat in warm weather. This glass tumbler is designed for enjoying your favorite beverages on-the-go. Whether you drink smoothies, iced tea, juices, or water, everything tastes better in glassware! 20 oz.