There are now four butterfly types. The regular one has a small hole in the bottom that allows it to attach to pins as on plant pieces. There is a small type that has a clip that will fit on typical round pieces. The third is a giant size introduced in 2013 as part of the Fairy theme, with a body having a System X type hole that takes any of the fairy wings with System X connector pins. The fourth is a small size first available in 2016 with a small pin.