Models of the Gundam robots are a major reason for the franchise's enduring success, which began in the 1980s. Hundreds of models, primarily plastic but sometimes featuring resin, metal and other types of detail parts, have been released. These range in quality from children's toy kits, to hobbyist and museum-grade models. Most models are of 1:35, 1:48, 1:60, 1:100 or 1:144 scale. Special promotional models of 1:6 or 1:12 scale are targeted to retailers and are not commercially available. One full size model was also constructed and displayed in Tokyo's Odaiba, and later in Shizuoka.