The Avent Express II Microwave Steam Sterilizer uses the power of your microwave to kill all household bacteria in only two minutes! Holds up to six 9 oz. Avent Natural Feeding Bottles, or two ISIS™ Breast Pumps and two 9 oz. Avent Natural Feeding Bottles. Contents remain sterile for up to 24 hours providing the lid is not removed. The lid is safely secured with two lockable clips. Cooler-touch safety grips on both sides of the sterilizer ensure easy handling.