"The Kowa TSN-884 3.5""/88mm Straight Spotting Scope is a world-class caliber instrument scope that redefines standards of color brilliance, sharpness and brightness consistency. Kowa reinvented themselves again with the TSN-884, fastidiously examining each technological and ergonomic detail to produce the very best all-weather straight viewing prismatic spotting scope. The TSN-884 uses an element of PFC (Pure Fluorite Crystal) glass in its construction, which greatly minimizes chromatic aberration. This ensures maximum efficiency in its light gathering, producing a clear visual range and sharp imagery that traditional glass lenses cannot attain at their highest magnifications and with the strongest of subject/background contrast changes. Fluorite is extremely expensive, but the subtle difference between the viewing from the Prominar-equipped TSN-884 and even the very best normal scopes would be apparent even to a novice. Kowa's use of their patented ""C3"" prism multicoating process increases image brightness significantly over their prior-generation models which featured fluorite.The 884's housing is made of a magnesium alloy that defines maximum durability and lightweight construction, resulting is a compact, ergonomic and functional design for extreme nature and outdoor enthusiasts wanting only the very best. It sets a benchmark for the combination of large objective with small weight and mass. As the straight viewing model of Kowa's flagship line, this scope|Fluorite crystal: Kowa uses the fluorite crystal exclusively in its flagship spotting scope and large binocular models. The fluorite used as make an optical lens is an artificially grown mono-crystal with ""ultra-low dispersion"", a character|XD-Lens: This lens has an outstanding optical performance and is easier to work with than fluorite crystal. When an XD lens (eXtra-low-Dispersion-lens) is paired with a concave lens with special dispersion properties, chromatic aberration is almost e|Compact: The telephoto lens design of using 5 lens elements in 4 groups has successfully shortened the overall length of the scope while keeping a large diameter objective lens without sacrificing optical performance|Dual focus mechanism (Quick and fine focusing): The well established Kowa focus system has progressed to a new dual focus system. The quick focus, with a large and easy to turn knob, will focus from infinity to five meters in two revolutions|Eyepiece locking mechanism: Kowa's standard eyepiece bayonet mount has been passed down to these new spotting scopes with a new attractive feature. An eyepiece locking|Magnesium alloy body: The magnesium alloy body made by a sophisticated molding process called thixotropic molding has the feel and strength of a traditional metal body with decreased weight when compared to other large-diameter scopes|Prominar Lens: One of the major causes of deterioration of viewing quality in optics is chromatic aberration. Chromatic aberration occurs due to the dispersion of light and the different wavelengths of light focusing on different positions, resulting"