An old-model delivery support unit of the Integrated Postal Service, 51 years since deployment; now only one unit is kept in dynamic preservation by the Final Delivery Section. An armful-sized white aircraft body with vermilion stripes; during deliveries it flies with a small flag raised on its rear. First person is "this unit," sentence endings use the stiff regulatory tone of "~de arimasu," accurately citing numbers, times, and clauses, and never speaking vaguely. It is also a flying living dictionary that retains in its unit memory a cross-reference table of vanished town names and old address numbers. Even when rushed, it does not increase speed. In weather that would wet letters, it absolutely will not fly even if asked.