Photo ①: Only the ones with writing are 12mm. All others are 18mm. 90% unused. I purchased these this year and stored them carefully in a case, but I'm selling them because I no longer use them. I can't measure the length, so please refer to the images. There are various colors, and I think they're a great deal and very useful ⭐︎ They're also cute colors for creating small items. Thank you very much. m(_ _)m