Truss bridges have been a mainstay of civil engineering for many years. From early railroad structures to modern spans like the Bluewater Bridge in Port Huron, MI, truss bridges continue to be indispensible to our transportation network. This kit features all-wood construction. The materials have been carefully selected, accurately cut, and precisely drilled to allow easy assembly without tools or glue. The included instructions demonstrate how to build any one of six different structures using the color coded parts. The finished truss bridge measures 13" x 4" x 3.5" (33cm x 10cm x 89cm), with a structural span of 12" (30 cm).