Model: Rangefinder 6x21 Objective lens aperture: 21mm Outlet pupil diameter: 4 mm Measurement distance range: 1000m speed measurement range: 0-300Km/h Prism: Bak4 roof prism Error in measurement: + 1m +0.1% Field of view: 122 m/1000m & 133yard/1000yard Type of coating: Fully multi-coated optics