Pigeon Breastfeeding Realization Nipple Set SS size: 3 pieces S size: 2 pieces Total: 5 pieces Used when feeding formula milk in mixed feeding. Also, the frequency of use varies because I bought more nipples along the way. Sterilized and stored at home. There is some yellowing, but they are still usable. Please refrain from purchasing if you are concerned about this. Shipping will be by anonymous delivery, and will be sent by post, with the tips folded. I am also selling glass baby bottles for newborns, so please take a look if you'd like.