Medela Contact Nipple Shields can be an effective tool for professionals and moms to temporarily assist with infants with latch-on problems, as well as for moms with overactive let-downs or for flat, inverted and sore nipples. Medela Contact Nipple Shield enables continued breastfeeding without interruption until these problems are resolved. Use under the guidance of a healthcare professional. Available in different sizes (16 mm, 20 mm, 24 mm). Nipple shield sizing will depend on the size of the infant's mouth. The use of nipple shields should be discontinued once problems are resolved. Comes with convenient carrying case.