Sony 500mm F8 Reflex is an Auto Focus (AF) Telephoto Mirror Prime lens with 35mm FF max sensor coverage. When mounted on a 35mm FF sensor camera, it will give you an FF equivalent focal range of 500mm. With the max aperture of only f8 at 500mm, it is considered a slow lens.
Sony 500mm F8 Reflex is not a weather sealed lens, so you have to be extra careful against rain and dust.