36mm PersonalFitTM Breastshields - 2 PacknAttaches to PersonalFitTM Connectors (not included)nOne size does not always fit all, so Medela developed PersonalFit Breastshields in a range of sizes to meet every mom's needs.Lactation professionals agree that proper breastshield fit is essential for not only comfort, but also for effective milk expression. Compatible with all Medela breastpumps. Made without BPA. PersonalFit connectors sold separately.