Kodak Duo Six-20
The Duo Six-20 is a 4.5×6 horizontal folder made by Kodak AG from 1933.
The original model has a folding optical finder and a key for film advance on the left of the top plate.
The Duo Six-20 Series II, released in 1937, has modified folding struts, a chrome top plate, an advance knob and an accessory shoe.
There is a rangefinder model evolved from the Series II, with a combined range- and view-finder under a top housing.
There are Japanese copies of the Duo, including the Semi Prux copying the original model, and the Roavic and Apollo based on the body of the Series II with some changes and the addition of a top housing.
- McKeown, James M. and Joan C. McKeown's Price Guide to Antique and Classic Cameras, 12th Edition, 2005-2006. USA, Centennial Photo Service, 2004. ISBN 0-931838-40-1 (hardcover). ISBN 0-931838-41-X (softcover). P. 491.