Bacteria in food multiplies quicker when stored at room temperature, the Nanobebe Breast Milk Bottle allows breast milk to be spread into a thin layer that cools quickly, reaching ideal refrigerated temperatures 2 times faster than standard bottles. It also warms 2 times faster than standard bottles, satisfying baby’s immediate hunger needs. The bottle’s domed shape and concave base make it ideal for tiny hands. It has an advanced, 360° venting system with two vents that release air even when covered by baby’s mouth, which reduces colic. A breast pump adaptor is included with each Breastmilk Bottle package. Using the breast pump adaptor you can pump directly into the nanobébé bottles using most standard breast pumps. These feeding bottles are also stackable, so you can save storage space and track pumping order. Size of bottle is 5oz (about 150ml). BPA, PVC, Lead and Phthalate free.