Gundam models, or gunpla, are assembly model kits depicting the vehicles and characters of the fictional anime Gundam universe by Bandai. Gunpla is very popular due to the high-quality of engineering, the flexible articulation of the finished models, the pre-coloured plastic parts, and the ease of construction. No glue is necessary to construct, though specialised plastic cutters or hobby knives are recommended to remove the parts of the sprue. Stickers and decals for markings are usually supplied, as well as an illustrated instruction sheet understandable in all languages.