Have fun building incredible structures with SmartMax! The new Start set includes 12 medium bars, three long bars, eight metal balls and a guide to build models. Extension sets are available separately. 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 since they are 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!