Travel and transport baby's bottles with ease with Dr. Brown's Convertible Bottle Tote. The insulated Dr. Brown's Convertible Bottle Tote bag is designed for your favorite baby bottles and carries up to four Dr. Brown's bottles. The Convertible Bottle Tote folds over and fastens for a snug fit to securely store shorter bottles or other small items like baby's food and snacks. Easily fold flat when not in use. Made with neoprene for a water resistant, insulated and cushioned bottle cooler, with an easy to clean interior and removable icepack.Dr. Brown's bottle features a patented two-piece internal vent system that works unlike any other bottle design. The vent system fully vents our bottle for vacuum free feeding, which we call positive-pressure flow, similar to breastfeeding. As the baby feeds, air is channeled from the nipple collar through the vent system, bypassing the breast milk or formula, to the back of the bottle. Air never mixes with the breast milk or formula which minimizes oxidation and helps maintain essential nutrients like vitamins C, A and E. Babies feed more comfortably because the vent system allows them to nurse without fighting the negative effects of a vacuum or the discomfort of ingesting air bubbles. This helps to reduce feeding problems like colic, spit-up, burping, and gas. The breast milk or formula flows freely, without nipple collapse. Includes two 4 ounce glass bottles with two level one nipples, two 2 piece internal vents and one nipple cleaning brush. BPA Free