This is an injection-plastic ship model kit.
The Japanese I-400 submarines were the most sophisticated subs of WWII, and were the largest non-nuclear submarines ever built. They were not only submarines, but also aircraft carriers, being able to carry, launch, and recover three Seiran aircraft. Captured by the US and studied intensely after the war, the I-400 and I-401 were scuttled off Hawaii in 1946, presumably to keep them and the technology out of the hands of the Russians.
Tamiya's kit of the I-400 can be built as either a waterline or full-hull model, and includes a very nice stand with nameplate for the full-hull version. Includes an excellent fret of photo-etched metal detail parts and parts for four Seiran aircraft, with options for folded or deployed wings and tails. Decals are included for the I-400 and its aircraft. A very impressive kit of one of the most impressive submarines of all time!
Tamiya's "Special Edition" release of their excellent I-400 kit includes clear parts for the hangar section and Seiran aircraft, metal torpedoes and photo-etched metal parts for railings (with self-adhesive "guide stickers"), and 48 injection-molded crew figures.