The ED82 features a large 82mm objective lens for the brightest image, & extra-low dispersion (ED) glass for chromatic aberration compensation & brighter, clearer viewing. The Nikon Fieldscope ED82 spotting scope has a helical focusing ring. Nikon makes a variety of fixed focal length, wide-angle, zoom & digiscoping eyepieces that fit the 82-mm ED Fieldscope. The Nikon Fieldscope ED82 comes with a sliding sunshade & padded view-through case. O-ring seals & nitrogen purging render the Nikon Fieldscope ED82 completely waterproof & internally fog-proof. The Fieldscope ED82 is manufactured with Nikon’s lead- & arsenic-free Eco-Glass.