At 144X magnification these binoculars can see the flick of a deer's ear 500 yards away. They can easily adjust from 20X to their maximum 144X with a simple press of a lever, providing sharp, clear images. Expertly collimated to provide a single image, they use powerful, fully coated optics, including 70mm objective lenses that offer superior light-gathering performance. They use a BaK7 porro prism system, providing a field of view of 131' at 1,000 yards. With an eye relief of 16 1/2 mm and a 3 1/2 mm exit pupil at 20X. They are shock-resistant, light, and easy to handle with their rubber grips; a tripod is recommended for stability at maximum zoom. Sturdy ABS construction. Includes carrying case and lens caps. 12 1/4" L x 8 3/4" W x 3 1/2" D. (4 lbs.)