At Paradigm, we are positively passionate about puzzles. Is your guy an architect, engineer, or just inherently analytical? Perfecto! This is the perfect gift for him. Build a working model of an old fashioned iron horse, 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.