Build a working clock with your own two hands, wind it up, then watch time pass with the swing of a pendulum and the meshing of gears. To assemble, pop the 170 laser-cut pieces out of the wood sheets and follow the included instructions. Estimated time about 5 hours. No glue, tape, or tools required. Finished size about 9½"w x 14"h x 4½"d. For ages 14 and up. The clock will run about 2-4 hours on a single winding.