Avent Comfort Breast Shell SetIf you decide to breastfeed, these breast shells are an absolute lifesaver during those first few months. The set contains two different shells that are worn inside your bra and over your nipples. The Ventilated Shells (with holes) provide exposure to air while creating a barrier between sore nipples and clothing, to aid in the healing process. The Breast Milk Saver Shells (without holes) allow for the collection of leaking milk and also help prevent embarrassing wet spots. The Ultra-Soft Silicone Backing Cushions can be used with both shells; they have petal-like massagers that gently provide added stimulation to relieve engorgement. An extra-wide opening for the nipple provides comfort and actually helps to draw out inverted or flat nipples.