This is a set of two Pigeon Mother's Milk Real Feeling M-size nipples. I purchased them at a store, but the M size didn't suit my baby, who had a strong sucking ability. I don't think we'll be transitioning to M size from S size, so I'm selling them. They are new and unopened, but have been stored at home, so there is a slight scratch on the outer box. It didn't show up in the photos. Thank you for your understanding. Thank you for looking. I've included a quote from the Pigeon product information for your reference. ↓↓↓ Made of durable silicone rubber. Recommended for babies from around 3 months old, M size (Y-cut). ※Even at the same age, there are individual differences in how babies drink. Choose the nipple that suits your baby, according to their growth and drinking style. ※One guideline for choosing a nipple is that it takes 10-15 minutes (5-10 minutes for babies 9 months and older) to drink the same amount as breast milk in one feeding. ●SS (round hole) 0 months and up (Drinking guideline: about 10 minutes for 50ml) ※For newborns ●S (round hole) 1 month and up (Drinking guideline: about 10 minutes for 100ml) ●M (Y-cut) 3 months and up (Drinking guideline: about 10 minutes for 150ml) ●L (Y-cut) 6 months and up (Drinking guideline: about 10 minutes for 200ml) ●LL (Y-cut) 9 months and up (Drinking guideline: about 5 minutes for 200ml) ●3L (Y-cut) 15 months and up For the weaning completion period ※Can also be attached to the old type of Mother's Milk Real Feeling (2nd generation) sold before February 2022. ※Cannot be used with slim type baby bottles.