This is an H&M dress set. When they are small, it can be worn as a dress, and when they get a little bigger, it can be worn as a tunic. The 80 and 90 size have buttons at the back of the neck. There is a stain on the back of the 80 size. How about for twins with a 1-2 year age difference? I am also selling many other matching outfits for sisters.