Compact monocular design - ideal for travel. Extra-low Dispersion glass for optimum clarity. Fully multi-coated optics to produce sharp images. Focus knob with 2 turns. High resolution phase corrected BAK-4 roof prisms. Lightweight rubber coated mid-size top hinge chassis. Stay-on lens covers for maximum lens protection. Twist-up eye cups with position stops for eye relief. Nitrogen purged water, shock and fog proof