Carson's 8x21 Tracker Binocular with 6.5-Degree Angle of View is a full featured binocular with fully-coated lenses that reduce internal reflections, and produce crisp, bright images. Special coatings provide unsurpassed infra-red and ultra-violet protection, reducing eye strain and improve image contrast. The Tracker has a center focus knob with an independent right diopter to adjust maximum focusing flexibility for all types of vision.