With Phase coated BAK4 prisms and fully multi-coated premium ED glass, Barska's Naturescape ED Spotting Scope takes optics to a higher level. Phase coating results in maximum resolution and optical quality by correcting or "phase shifting" the light that is reflected off the prisms and optimizing it for the scope's aperture size. ED (Extra Low Dispersion) glass provides you with views of exceptional clarity and resolution. Compared to conventional achromatic lenses, ED glass lenses minimize chromatic aberration and other forms of distortion resulting in higher resolution and contrast. 100% waterproof and fogproof, this scope is at home in the most demanding environments and is ruggedly built to withstand the effects of movement from one location to another. Includes deluxe hard carrying case and lens cloth. Protected by Barska's Limited Lifetime Warranty.