This is an injection-plastic aircraft model kit.
From the Aoshima description:
Kawasaki Ki-100 II is a high altitude fighter equipped with the Mitsubishi Ha-112-11 Ru engine, which generates 1,000PS at an altitude of 10,000m. The Kawasaki was designed to intercept the B-29 bombers. The development started in Nov. 1944 and the first prototype was completed in May 1945. Only 3 were built due to the end of World War II.
Parts come molded in gray. Kit includes decals.