Medela's Contact Nipple Shield can be an effective tool for moms to manage infants with latch-on problems, for moms with overactive let-downs or for flat, inverted and sore nipples. Medela Nipple Shields enable continued breastfeeding without interruption until these problems are resolved. For latch-on difficulties or flat/inverted nipples. Unique cut-out shape for more skin contact between mom and baby. BPA-Free. Available in 3 different sizes (16mm, 20mm, 24mm).