All Frontier models feature Hawke&';s H7 optics, offering stunning high definition viewing with incredible color control and phase correction. High performance lens coatings and Dielectric Coated prisms ensure the highest level of light transmission. The Frontier APO offers extreme clarity, flat field vision along with excellent chromatic aberration control for a stunning wide angle image. APO models benefit from Extra-low Dispersion glass for controlled chromatic aberration and the elimination of color fringing. Features: APO Lenses Extra-low Dispersion (ED) glass Dielectric Coatings High resolution phase corrected BAK-4 roof prisms Water repellent lens coatings Magnesium alloy chassis Focus from 2m Replaceable twist-up eye cups with position stops Stay-on lens covers