With this new SMARTMAX® magnetic construction set you can build all kinds of houses and towers. This extensive set contains special new construction parts, including a window you can open and close. There's no place like home. 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 unqiue 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.