Product description Bushnell Falcon 10x50 Porro Prism Black Binoculars 133450 Amazon.com Bushnell is the leading brand in high-performance binoculars, and the Falcon series offers powerful magnification at an economical price. Versatile, and ideal for stadium sports, bird-watching, hunting, and many other outdoor applications, the 10x50 model boasts a durable design and rubberized, abrasion-resistant finish. An InstaFocus lever provides smooth feedback, with just enough tension to fine-tune magnification, while a Porro prism and coated lenses provide sharp viewing. For those who wear eyeglasses, or sunglasses on bright days, clever fold-down eyecups protect your lenses from scratching.Making Eye Adjustments (Figure 1): The distance between the eyes, called ?interpupillary distance,? varies from person to person. To achieve perfect alignment of lens to eye, follow these simple steps. Hold your binocular in the normal viewing positionGrasp each barrel firmly. Move the barrels closer together or further apart until you see a singular circular field. Always re-set your binocular position before using. Improper alignment of the interpupillary distance can cause double-images. How to Adjust for Individual Eye Strength: Bushnell Falcon binoculars utilize the ?Insta-Focus? focus system. "Insta-Focus" binoculars have a central focusing lever between the barrels. Focus at any far or near distances can now be attained simply by pressing the ?Insta-Focus" lever. Eye Cups (Figure 3): Bushnell Falcon binoculars are fitted with rubber fold-down eyecups designed for your comfort and to exclude extraneous light. If you wear sun/eyeglasses, roll down the eyecups. This will bring your eyes closer to the binocular lens thus providing improved field of view. Specifications:Magnification/Lens Diameter: 10x / 55mmAuto focusing Porro prism25-foot close focusing distanceWeight: 27 oz.Eye Relief: 9mmExit Pupil: 5mmField of View @ 1,000 yds: 300ft Handy fold-down eyecups prevent prescription glasses and sunglasses from scratching