Once you have selected a breastpump that best meets your needs, you will need a proper fitting breastshield. A breastshield fits directly over your nipple and attaches to the pump kit, which is connected to the pump with tubing. The breastpump creates a vacuum which gently draws your nipple into the breastshield, removing milk from your breast. A correctly sized breastshield provides comfort while you pump is proven to maximize milk flow. Medela has developed the PersonalFit Breastshield System designed to ensure moms who pump can find comfortable, well-fitted breastshields.