The Vortex Crossfire HD is the new and improved version of the Vortex Crossfire series. Vortex has equipped the Crossfire HD 10x50 binoculars with an improved HD optical system with fully Multi Coated lenses. This ensures a higher light transmission giving you brighter and sharper images than its predecessor. The Vortex Crossfire HD 10x50 binoculars are also equipped with a Vortex Glasspak Binoculars Harness in which you can properly protect your binoculars when you are not using them. This bag can easily be hung on your chest so that you can take it with your hand. strong Application Vortex Crossfire HD 10x50 Binocularsstrong When the Vortex Crossfire HD 10x50 is worn in the Glasspak Binocular Harness on your chest you can open the bag with your thumb and index finger and then immediately remove the binoculars from the bag and use them. When looking through the binoculars it is important to see a circle this can be achieved by moving the eyepieces from or towards each other. When the circle is complete close your right eye and focus with the focus wheel in the center on top of the viewer. When you see a sharp image open your right eye and close the left one. Now you can rotate the dioptric ring until you also see a sharp image with the right eye. The dioptric ring is located beyond the eyepiece rubber of the right eye. When you see a sharp image you can open your eye and the Vortex Crossfire HD 10x50 Binoculars are ready for use. It is also possible to increase the distance between your eyes and the eyepiece by turning the eyepieces. These so-called Twist-Up eyepieces allow you to look through the binoculars even more comfortably. The maximum eye distance can be set in a smooth movement up to a maximum of 17mm.