18 X 50 IS All Weather Features Built-in Image Stabilizer (IS) provides shake-free performance High magnification ratio: 18X Ultra-low dispersion (UD) glass elements for exceptional image quality Doublet field-flattener for sharp, distortion-free images from edge-to-edge Extra-bright, large diameter 50mm objective lens Long eye relief: 15mm Water-resistant construction with non-slip rubberized grip High-Power, Large Binoculars Perfect for Star Gazing or When You Can't Get Close Enough. (Featuring an Image Stabilizer and All-Weather design.) With its wide 50mm objective lenses and high magnification,these rugged, all-weather Canon Image Stabilizer binoculars are destined to set a new and higher benchmark for image brightness, clarity and ergonomic design Binocular Specifications Type Prism Binoculars Magnification 18x Objective Lens Effective Diameter 50mm Filter Size 58mm Real Field of View 3.7° Apparent Field of View 66.6° Objective Lens Construction 4 elements in 3 groups (including protective glass) Eyepiece Lens Construction 7 elements in 5 groups Exit Pupil Diameter 2.8mm Eye Relief 15mm Prism Type Porro II Eye Width adjustment 58mm ~ 76mm Focusing Method Manual focusing by turning the focusing knob Dioptric Correction ±3.0 diopters Closest Focusing Distance 6 m/19.7 ft. Image Stabilizer Vari-Angle Prism Correction angle ±0.7° Tripod Socket Provided Power Source 2 x AA Dimensions 152 x 193 x 1180mm/6.0 x 7.6 x 3.2 in. Weight 1180g/41.6 oz. (excluding batteries)