Top hinge - exceptional mid-size optical performance. 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 turns. 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. Twist-up eye cups with position stops for eye relief.