The Nikon TC-201 is a 2x teleconverter that doubles the focal length of a compatible Nikon lens. A 200mm lens, for example, effectively becomes a 400mm lens, bringing distant subjects closer. The converter reduces the available light by two stops and is designed for use with compatible Nikon F-mount lenses. A useful accessory for wildlife, sports and other types of photography where extra telephoto reach is desired. Serial number 362598.