This is one S-size nipple from Pigeon's Mother's Milk Realization series. I used it a few times after sizing up, but my baby started refusing the bottle, so I stopped using it. Therefore, it hasn't been used much. When shipping, I plan to flatten (indent) the center of the nipple. - Brand: Pigeon - Size: S - Quantity: 1 piece Please comment if you have any questions. Thank you for looking.