These micro-sized 3D building blocks from Nanoblock are the hottest thing since Lego! With over 390 assorted size and colored pieces (most around .25" long and 1/8" tall), watch in amazement as the Chrysler Building takes shape. When it's finished, it will fit into the palm of your hand! Includes detailed color instructions. Definitely not designed for children under the age of 8 years. I'm telling you - these pieces are really tiny (I couldn't do it)! Level of difficulty on this one is a 2 - with "5" being most difficult. All you need is a little time and a whole lot of patience!