Spin-Gineer lets budding engineers safely weld together plastic beams with friction, constructing awesome structures using real-life techniques. Follow along with the plans to assemble a bridge almost two feet tall or design your own structures. Once the beams are in place, watch as the welding mechanism spins the rods so fast that the plastic melts and molds the structure into place. What a sight to behold! Includes over 200 pieces that snap apart for repeated use. Welding pack requires four D batteries (not included).