This is a Kodak Retina Reflex IV type 051 35mm Single Lens Reflex camera made by Kodak AG in Stuttgart, West Germany between the years 1964 and 1966. The Retina Reflex series was a continuation of the earlier rangefinder Retina, and shared many of the same parts, including the body, lens mount, and leaf shutter. The leaf shutter in the Retina Reflex would prove to be problematic over the years which prevented them from being considered a serious SLR platform. Despite the unreliable shutter, the Retina Reflex series maintained the high quality standard of earlier Retinas, and included well-built lenses that had excellent optics. The Retina Reflex IV was not only the last Retina Reflex, it was also the last “true” Retina camera, and the last time Kodak would ever build their own analog SLR. The camera has the synchro Compur-X leaf shutter with speeds of 1 second to 1/500 of a second plus B. The camera also has a Gossen selenium cell exposure meter with a match needle visible in viewfinder. The 50mm Schneider-Kreuznach Retina-Xenon f/1.9 coated 6-elements lens was the one that came with the camera and very fine ones can command $90.00 today. The camera has a Retina bayonet mount (front group only) lens mount and a Hot Shoe plus PC socket X sync. The Retina Reflex IV originally sold for $277 USD and over 524,000 were made of the 051. In 1977 an unknown quantity of Retina Reflex IV (051/N) cameras were hand assembled from spare parts at Kodak A.G. in Germany. The only difference was the lack of a serial number on top of the pentaprism and the body number is embossed on the leather of the back cover rather than printed in the film compartment. The N stands for New. Some of this information was gathered from the mikeeckman.com web site, Wikipedia, and McKeown’s Price Guide.