Philips Avent microwave steam sterilization bags allow you to quickly, easily and efficiently sterilize Baby bottles and Baby products anywhere, anytime. Bottles can be sterilized in the microwave in only 90 seconds per bag. Each bag package for steam sterilization in the microwave contains five individual bags. Each bag can be used up to 20 times. This means you can sterilize up to 100 Baby bottles, breast pumps and other accessories with just one package. Each bag contains a check box. By checking the checkboxes, you can easily track how often you have used each bag. Microwave steam sterilization bags have been proven to kill 99.9% of germs and bacteria.