“R” is for Retina. Kodak has a series of cameras with the Retina name.
The pre-war Retina was very much a tiny bellows camera designed for the newly developed 35mm film cartridge.
Later, it was a simple viewfinder camera, still maintaining the fold-out lens.
The Automatic III had a coupled rangefinder, to make focusing easier. However, it no longer has the fold-out lens.
The other cameras featured in this A to Z Challenge are linked on this page.