Cooler bag the ideal solution for active mothers medela have developed a system which enables you to keep your expressed breastmilk cool and safe even on the go with the special cooler bag you can transport up to four bottles of breastmilk safely in addition to your breastpump the insulation on the inside of the bag will keep the expressed breastmilk cool for longer includes 1 x specially formed cooling element 4 x 150ml breastmilk bottles features transports and