Baby King Plastic Sterilizer is compact and lightweight structure makes it perfect for travel. The microwave sterilizer works by using heat, generated by steam created when the product is filled with a specified amount of water and then heated in a microwave oven. The Microwave Steam Sterilizer has safety clips that keep the lid firmly in place and allow you to remove from the microwave safely, without the risk of burning yourself. It can also be used for bottle storage, BPA-free natural bottles, made of polypropylene. The duration of the cycle depends on the power of your microwave.