Extra-low Dispersion glass for optimum clarity. Dielectric Coatings provide increased light reflectivity. Fully Multi-Coated optics to produce sharp images. Focus knob with 1.5 turn - close focus 6.6ft/2m. High resolution Phase Corrected BAK-4 roof prisms. Water repellent coating on objective lenses. Lightweight rubber coated magnesium alloy chassis. Stay-on lens covers for maximum lens protection.Replaceable twist-up eye cups with position stops