Breastfeeding Consultation Room - SM size nipple for baby bottles. The other 3 I listed are sold out. The SM size currently listed is somewhat rare, as it was recently discontinued. Now only SS size is sold. The SS size has a small hole for newborns and babies with weak sucking strength. The SM size, on the other hand, has a slightly larger hole, and is used by babies a few months old. My 1.5-year-old child has strong sucking strength, and other nipples like the Pigeon breastfeeding simulation and NUK would collapse while drinking. However, this one didn't collapse and worked well, so I stocked up on them until my child was 1 year old. ※ I also have various other items for sale, such as toys and baby clothes, so please take a look if you're interested. I offer discounts for combined purchases. There are no major scratches or stains, but please understand that there may be some signs of use from daily use. Preparing for childbirth, breastfeeding, formula, baby, newborn. Please purchase with your understanding.