Four additional track sets for use with Force & Motion: Pushes & Pulls Kit. Assembly required.Force & Motion: Class Set of Four TracksSKU: 1-012Contact Us to PurchaseKit Contents Metersticks Track Connectors Die Cast Cars Marbles Wooden Balls Steel Balls Rubber Balls Felt Plastic Sheet Burlap Foil Sandpaper Shipping Weights and DimensionsBox 1 Sh. wt. 10lbs, DIM 9” x 9” x 5” Box 2 Sh. wt. 8lbs, DIM 8” x 16” x 40”