The Pentax 8 x 40 PCF WP II Binoculars feature large objective lenses for superior light gathering in even the lowest light conditions.Nitrogen filled waterproof (JIS class 6) construction allows these binoculars to be used in the most extreme weather conditions and to be submerged to 1 meter. Aluminum diecast body adds strength and durability. Long eye relief for viewing without glasses. Mechanical focus lock feature allows user to lock in at specific distance for convenient focus free viewing. Click-stop diopter adjustment locks in right eyepiece diopter setting. Ruggedly constructed with a rubber housing to protect the internal optical and mechanical systems. Helicoid eyepiece ring with four click stops give the most comfortable eye relief. Binocular Type: Porro Prism center focusing (built in focusing arm). Lens construction: 2 elements in one group. Coating: Lens-full multi coating, Prism multi coating. Magnification: 8 X. Objective Lens: 40 mm. Real Field of View: 6.3 degrees. Apparent field Of View: 50 degrees. Field Of View at 1000 Meters: 110m. Field Of View at 1000 Yards: 330 Ft. Exit pupil: 5.0 mm. Eye Relief: 20 mm. Relative Brightness: 25. Diopter Adjustment Range:+/-2m-1. Eye Width Adjustment Range: 57 mm to 72 mm. Focusing Range: 11.5 ft. Eyepiece Ring: Heliciod type. Size: Height-5.5 in. Width- 7.0 in. Weight: 28.2 oz.