The Boob Glass Bottle is the most innovative baby bottle on the market today. The nipple design, CleanFlow Vent System, silicone sleeve, and bottle are state-of-the-art and use today's best design and materials. This set includes three glass bottles and one silicone sleeve. Some old fashioned things just can't be improved upon and the Boob Glass Bottle is a classic example. Glass does not absorb odor, color or taste, so it is an excellent material for baby bottles. The Boob Glass Bottle can withstand a sudden temperature change of 176-degrees Fahrenheit/80-degrees Celsius. The silicone sleeve reduces slips and provides an excellent cushion against bumps and drops. Transitioning from breast-to-bottle, bottle-to-breast, or bottle-to-bottle can be frustrating and delicate, but the Boob Bottle's innovation and technology make it a "natural" choice for quick and easy transitions. Dishwasher safe. Available in 5oz and 8oz sizes.