Specification  Magnification factor:8x/10x Eyepiece diameter:20mm Objective diameter:42mm Eye relief:19mm/18.5mm Exit pupil diameter:5.25mm/4.2mm Field of view: 5.5°/4.65° Prism type:BAK4 Lens type:All-ptical Glass Lens Coating of Lens:FMC multi-layer green coating Waterproof grade:IPX5 Weight:680g Product size:151x126x56  Feature  1. High-quality BaK-4 prisms combined with fully multi-coated optics increase contrast and resolution byproviding maximum light transmission through the entire optical path delivering you brighter, moredetailed images. The twist-up eyecups with multiple positions ensure comfortable viewing with or withoutglasses. 2. The 10x magnification works great for long distance viewing and the 42 mm objective lenses gather ample light for use in lowlight conditions. . With the semi-attached objective lens caps you’ll be able to keep your lenses protected at all times. Plus, the large, smooth focus wheel is easy to turn allowing you to focus on subjects at varying distances even with gloves on. 3. Waterproof, fogproof, and nitrogen purged, sturdy enough to withstand the elements on your next outdoor excursion. The polycarbonate housing is extremely durable and able to endure rugged use in the field while remaining lightweight.