NUK Perfect Match Nipple for Baby Bottle, Size M, Round Hole 2 pieces I am selling these because I accidentally bought the wrong ones. I opened the package once to try to attach them, but they didn't fit my baby bottles, so I haven't used them. When shipping, I will take the nipples out of the outer box and ship them via Yu-Packet Post. (I will fold the outer box for shipping) Please understand that the package has been opened before purchasing.