Get on Amazon : http://www.amazon.com/gp/product/B003AQIX5A?tag=lottalatte-20

Vortex Viper PST 6-24x50 Rifle PST-624S1-M

Optically Indexed Lenses Delivers optimum image sharpness and brightness with true reticle use for full ranging and holdover from edge to edge because of computer-controlled alignment during construction
XD Lens Elements Extra-low dispersion XD glass enhances resolution color and contrast
XR Lens Coatings Vortex XR proprietary anti-reflection lens coatings increase light transmission with multiple coatings on all air-to-glass surfaces
30 mm Tube Provides greater strength and wider adjustment latitude as compared to a 1-inch tube
One-Piece Tube Maximizes alignment for improved accuracy and optimum visual performance as well as strength and waterproofness :