The X-TRAC was designed to aid the shooter in a dynamic shooting environment. Have all of your controls at your fingertips and never get bogged down in a mission critical situation. Six tactile buttons and a directional roller with touch feedback gives you precise control over all your features. Using your Ballistic Calculator, Smart Rangefinder, Environmental Adjustments, etc on your Smart HD Scopes just got easier. Battery life lasts 6 months.