One 21mm breast shield for comfortable pumping. - Brand: medela - Product Name: PersonalFit Flex Breast shields - Size: 21mm - Quantity: 1 piece - Features: BPA-free I purchased this separately because the breast shield that came with my breast pump set didn't fit. I only needed one, so the other one is completely unused. Since it's unused, the white protective cover on the breast shield is still attached. (I believe this is proof of non-use, as it can't be reattached once removed.) If you need the outer box, I will ship it flat. Thank you for looking.