Marathon 7x50mm BAK-4 Prism Binocular with Compass Black. The model features a navigational compass with backlight built into the viewing optics as well as vertical and horizontal NSN reticles to assist in measuring distance during operation. This binocular is also specially designed with a magenta lens coating to increase image brightness. Engineered with a premium BAK-4 prism it offers an excellent viewing experience with superior light transmission and less peripheral light being lost due to internal reflection. This binocular is built to thrive in any environment; waterproof and submersible to a depth of 0.5m for up to 20 minutes and featuring a nitrogen-filled case to prevent fogging of the lenses during changes in heat or humidity. Specifications for Marathon 7x50mm BAK-4 Prism Binocular W/Compass: Manufacturer: Marathon Color: Black Magnification: 7 x Objective Lens Diameter: 50 mm Prism Material: BAK-4 Eye Relief: 0.8 in Exit Pupil: 5 mm Field of View Linear: 370 ft at 1000 yds Optical Coating: Coated Glass Weight: 2.9 lb Package Type: Box Package Contents: Marathon 7x50mm BAK-4 Prism Binocular W/Compass Marathon BI030017: 7x50mm BAK-4 Prism Binocular with Compass Black