High-Performance Model with Superior Optics A 77mm objective lens in a compact body. With the portability and compactness of a 60mm class scope and the optical performance of an 80mm class scope, this model will satisfy both experienced users and beginners. 77MM XD LENS: The PROMINAR models have an XD objective lens with low dispersion properties to diminish chromatic aberration. Like the TSN-880 Prominar models, the concave lens paired with the XD lens is made of glass with special dispersion properties to reduce the chromatic aberration to a further degree. COMPACT SIZE: The adoption of the inner focus system keeps the prism box light and compact, realizing a large 77mm objective lens in a body length of a 60mm class scope. MAGNESIUM ALLOY BODY: The magnesium alloy body decreases the weight of the scope while providing a rugged structure that can withstand the severest conditions. DUAL FOCUS MECHANISM (QUICK & FINE FOCUSING): The dual focus mechanism allows focusing in two revolutions and fine pinpoint accuracy in one system. EYEPIECE LOCKING MECHANISM: The eyepiece locking mechanism secures the eyepiece to the scope body and prevents it from getting lost or falling off suddenly. TRIPOD MOUNT: The addition of a brass insert to the tripod mount of the scope allows the scope to be secured to both 1/4 and 3/8 inch mount tripods. WATERPROOF & FILLED WITH DRY NITROGEN GAS: The housing is waterproof to JIS* Protection Class 7** and filled with dry nitrogen gas to prevent the lens from fogging. *JIS=Japanese Industrial Standard **The Scope is not intended for use underwater Kowa TSN-773 77mm Prominar Angled Spotting Scope Body