Size: ・Length: 390mm ・Outer Diameter: 30mm ・Inner Diameter: 24mm ・Thickness: 3mm Number of pieces: 8 I think these can be used for DIY projects, summer vacation crafts, etc. These are made of a very hard material that won't crush even if an adult stands on them. I was using them as a bookshelf rack by fitting parts together. There are no cuts or markings, but please consider that these are used.