Dr. Brown's Microwave Steam Sterilizer Bags are convenient, BPA-free bags to help sterilize baby bottle parts when travelling or out and about! These bags are designed to fit all Dr. Brown's baby bottle partsand help to eliminate 99.9% of most household bacteria and germs. Simply wash the bottle parts, pop them in the steriizer bag and in to the microwave it goes! Each bag is reusable up to 20 times and each box comes with 5 bags.