Spotting Scope: Effective objective lens diameter (mm): 80 Eye relief (mm): 17 Shortest focusing distance (ft / m):16.4 / 5 Diopter correction at ∞ (dpt): > 5 Objective filter thread: M 82 x 0.75 Functional temperature: -13 °F to +131 °F (-25 °C to +55 °C) Storage temperature: -22 °F to +158 °F (-30 °C to +70 °C) Submersion tightness: 13 ft (4m) water depth (filled with nitrogen) Eyepiece: Magnification: 20-60x Exit pupil diameter (mm): 4.0-1.3 Field of view (ft/1000 yds / m/1000 m): 108-60 / 36-20 Field of view (degrees): 2.1-1.1 Field of view for spectacle wearers (degrees): 2.1-1.1 Field of view. apparent (degrees): 40-65 Light transmission (%) total product: 86 Weight angled view (oz / g): 57.8 / 1640 Length angled view (in / mm): 15.8 / 400