Vortex Viper HD spotting scopes are offering a brilliantly clear image and contrast manly because of their high build quality. The light dispersion is essentially small because of the HD glass, from which the lenses are made and consequently the optical properties are just excellent, the image has high contrast as well as resolution. The lenses are made accurately and covered with multilayer coatings to assure even more contrast and high resolution image. A special XR lens coatings are offering a high light transmission rate which enables the usage of spotting scope even at dusk conditions. The spotting scopes are sealed with o-rings and are therefore water-resistant. The Vortex guaranties for 100% waterproofness of Viper HD housings. Lenses are also covered with a special outer lens coating to protect them from dirt, mud, oil and other damage.