A Sunagor telephoto — an obscure brand 200mm of unknown mount and quality.
The Sunagor 200mm f/3.5 is a telephoto prime from Sunagor, a Japanese brand associated with OEM and budget lens production marketed under the Sunagor label in various markets during the 1970s–1980s. The null mount indicates the specific camera system version of this example is unconfirmed.
The lens delivers 200mm at f/3.5 maximum aperture with manual focus, manual aperture, and full-frame 35mm coverage. The f/3.5 maximum aperture is faster than many competing 200mm lenses of the era. Mount type would require physical inspection to confirm.
Sunagor lenses were sold as affordable telephotos for amateur photographers. The f/3.5 aperture at 200mm provides more light gathering than typical consumer 200mm f/4 or f/5.6 designs. Adapter availability for modern use depends entirely on which mount version this is.
Identify mount type from physical inspection before considering adaptation. Test focus ring and aperture operation. Inspect elements for haze or oil. The specific mount is required information before purchasing.