The crisp and clear images provided by the Tracker 10 30x25 Zoom PC I binoculars comes via a fully multi coated lens for excellent image brightness and contrast and BaK 4 prisms with a high refractive index for edge to edge clarity. High index BaK 4 prisms for a bright, crisp image from edge to edge Compact, lightweight design for hassle free portability Contemporary design is sleek and stylish Fully multi coated lens for maximum image brightness and contrast Twist up/down eyecups Special optical materials provide protection from harmful UV rays Built in dioptric correction adjusts to individual eyesight Convenient center focus knob for easy, accurate focusing