Simply place it over the nipple. It draws out flat or inverted nipples, correcting them to a shape that is easier for breastfeeding. ■ For correcting flat or inverted nipples ■ Made of soft silicone rubber ■ Contains 2 pieces, with a storage case - Included: Instruction manual - Sterilized Thank you for viewing. I used this as a breastfeeding aid for my first child, and I was able to successfully breastfeed exclusively. I am offering it for sale in the hopes that someone who needs it can use it. I have sterilized it by boiling it at home, but I recommend that you sterilize it again at home after purchase before use. When shipping, the case will be folded for packaging. Please be aware of this.