Truss bridge (this item) Suspension bridge, cable stayed bridge. How many can you build with the shapes and pieces in each of these sets? Or build with more than one Mini Unit kit to expand the possibilities even further. These unique sets encourage explorative play and introduce math concepts, logic, and problem-solving. Truss Bridge Kit : 220 pieces; Ultimate Bridge Kit (WD0472, sold separately): 15 shapes, 19 wood bricks, 620 unit beams; Cable Bridge Kit (WD1142, sold separately): 200 pieces. No additional tools needed. BPA-free, 100% earth friendly, made with organic paints and dyes. Ages 6+.