Your Breast Milk, Kept Cool: This cooler set lets you easily transport up to four 5-oz bottles, keeping milk at a safe temperature for up to eight hours until you can get to a refrigerator Fits Right In: Designed to fit seamlessly inside the Sonata, Freestyle, and Pump In Style bags for a straightforward way to carry all your breastfeeding supplies Compatible with Medela 5 oz Bottles: Both the cooler bag and contoured ice pack are compatible with Medela 5 oz milk bottles, which are also included with the Swing and Harmony breast pumps for ease and convenience Trusted Medela Quality: This set and its accessories are crafted with the high standards moms around the world have come to expect; inauthentic spare parts may vary significantly in terms of quality Peace of Mind: Our shatterproof feeding bottles are made without BPA, giving you one less thing to worry about and ensuring the highest safety for your baby