The Medela Contact Nipple Shield is used for cases of latch-on difficulties or inverted nipples. The unique cut-out base of the shield allows more skin to skin contact between mother and baby. Autoclavable. Medela's shield is made of silicone and DEHP & BPA free. For use under professional care only while breastfeeding the baby. Not to be worn between feedings. Sizes range from 16mm to 24mm.