At Paradigm, we are positively passionate about puzzles. Kids of all ages love our 3-D puzlles (and we mean adults too)! Build a working model of a zeppelin on wheels, wind it up, and watch it go, powered by a metal spring. To assemble, pop the 349 pieces out of the wood sheets and follow the included instructions. Estimated assembly time about 4 hours. No glue, tape, or tools required. Finished size about 12" long x 10" high x 8 ½" deep. For ages 14 and up.