APO System Index-matched lenses correct color across the entire visual spectrum. Optically Indexed Lenses Optimize image sharpness and brightness from edge to edge. HD Lens Elements Premium extra-low dispersion glass delivers the ultimate in resolution and color fidelity, resulting in high-definition images. XR™ Plus Fully Multi-Coated Ultimate anti-reflective coatings on all air-to-glass surfaces provide maximum light transmission for peak clarity and the pinnacle of low-light performance. Plasma Tech Cutting edge coating application process provides unparalleled coating durability and performance First Focal Plane Reticle Scale of reticle remains in proportion to the zoomed image. Constant subtensions allow accurate holdover and ranging at all magnifications. Glass-Etched Reticle Allows for intricate reticle design. Protected between two layers of glass for optimum durability and reliability. Illuminated Reticle Provides precise aiming under low-light conditions