Build the ultimate ball track with this new Smartmax magnetic construction set that contains an amazing 74 pieces! With endless options you can make all kinds of crazy machines and let the balls roll. mega ball run contains special parts including tubes and X-shaped bars with 4 magnetic ends. smartmax enables young children to explore magnetism safely, with strong, oversized pieces that are specifically designed for handling by young kids. smartmax products are safe and durable, made from the highest quality materials. Our magnets are incredibly strong, able to carry up to 60 times their own weight! smartmax magnetic bars feature unique color codes: "Cold"-colored bars (blue, green, purple) attract "warm" colored bars (red, orange, yellow). warm-colored bars repel other warm-colored bars, cold-colored bars repel other cold-colored bars. smartmax products include complete, colorful guides with both product information and sample designs. all parts can be combined with all existing Smartmax sets, creating an endless range of possibilities.