National geographic 8x42 Roof Prism Binoculars. High quality, versatile waterproof binoculars. Twist-up eyecups to cater to observers with or without glasses. Featuring Bak-4 prism, the 8x42 is fully multi-coated to provide great colour fidelity and high contrast. Objective caps allow you to keep your objective lenses protected when not in use, and allow for quick and easy opening and closing. FEATURES: Dimensions H: 5.5cm x W: 13cm x D: 15cm, Weight: 710g Magnification: 8x, Objective Lens Diameter: 42mm Linear Field of View: (@1000m) 109m, Waterproof Roof Prism