The LEGO Ultimate Building Set (6166) is a popular toy with 405 pieces, perfect for children aged 4 and above who have an interest in building. This set, released in 2007, allows kids to create and design various structures, stimulating their creativity and problem-solving skills. With a blue color scheme and packaged in a bucket/tub, this complete set by LEGO is ideal for young builders looking to expand their collection of building blocks.