The Medela Nipple Shield in medium size is a breastfeeding aid designed to help mothers experiencing nursing difficulties. Made of soft, BPA-free silicone, it comes with a convenient storage case for hygienic protection between uses. The product includes two clear silicone nipple shields and a yellow protective storage case. Being a personal hygiene product used during breastfeeding, it should be thoroughly cleaned and sterilized before each use. The medium size is suitable for most mothers, but Medela offers different sizes to ensure proper fit.