The sterilizer bottle works with steam and kills 99.9% of all bacteria. When feeding with the bottle or pumping milk, four to six bottles in a day are sufficient. That's a lot of cleaning work that you can leave to the sterilizer bottle. Your bottles will be ready for use again in just six minutes, and you won't have to worry anymore. This microwave sterilizer is made from BPA-free material and is quick and easy to use.