Kite Optics Vireo Pocket Binoculars Black. It features roof prisms. The roof prism construction brings important advantages such as waterproofing and nitrogen gas filling internal focus mechanisms that result in robustness and an overall very compact sized optical system. Specifications for Kite Optics Vireo Pocket 10x28 Binoculars: Manufacturer: Kite Optics Color: Black Magnification: 10 x Objective Lens Diameter: 28 mm Prism System: Roof Prism Material: BAK4 Eye Relief: 15 mm Exit Pupil: 2.8 mm Field of View Linear: 86 m at 1000 m Field of View Angle: 4.9 degrees Optical Coating: KITE MHR Binoculars Focus System: Central Twilight Factor: 16.7 Interpupillary Distance: 35 - 69 mm Close Focus: 2.9 ft Diopter Adjustment Range: 3 - -3 dpt Water Resistance Level: Waterproof Length: 8 in Weight: 250 g Finish: Cardboard Package Type: Box Width: 105 mm Last Chance: Yes Features of Kite Optics Vireo Pocket 10x28 Binoculars Extremely small sized and light 2 stage twist up eyecups Robust construction KITE MHR+ coating Great image sharpness Waterproof and nitrogen gas filled 30Y warranty Package Contents: Kite Optics Vireo Pocket 10x28 Binoculars Lens Covers Strap Pouch Kite Optics KOVIR1028: Vireo Pocket 10x28 Binoculars Black