The Vortex Razor HD 22x Ranging Eyepiece is specifically designed for use with the 27-60x85mm Razor HD Spotting Scope. When used in conjunction with the Razor HD Spotting Scope, range work, calling shots, and spotter/shooter communication become seamless. It's essentially like having a ruler in your spotting scope-which comes in quite handy. The ranging eyepiece comes with a MRAD reticle to match with the reticle subtension markings and turret graduations in your riflescope.