Have fun building incredible structures with SmartMax! The Start Plus set includes 23 pieces and a colorful guide to build models. SmartMax enables young children to explore magnetism safely, with strong, oversized pieces designed for small hands. 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. Designed for ages 3+, kids will be enthralled by the tactile process of clicking bars and metal balls together. All SmartMax sets are compatible with each other, so kids can start building and keep building with endless possibilities. Award-winning and built with high-quality materials, including sonically welded bars, SmartMax products are safe and durable. Extension sets are available separately.