Olympus Tracker 10-30x25 Zoom Porro Prism Compact & Lightweight Binocular 10x to 30x magnification and 25mm objective lens Field of view: 56 to 33 meters (at 1,000 yards) High-index prisms for a bright, crisp image Compact and lightweight for portability Twisting eyecups for personal comfort; central focus knob and dioptric correction