The Kawanishi H6K was an Imperial Japanese Navy flying boat produced by the Kawanishi Aircraft Company and used during World War II for maritime patrol duties. The Allied reporting name for the type was Mavis; the Navy designation was "Type 97 Large Flying Boat" (九七式大型飛行艇?).
Read more about Kawanishi H6K: Design and Development, Operational History, Variants, Operators, Specifications (H6K4)