“SpecterDR represents a revolution in optical sight design. The world’s first truly dual field of view combat optical sight that combines the best of close and precision fire ranged combat features. SpecterDR switches instantly from 4x magnified sight to a 1x CQB sight at the throw of a lever. Unlike zoom sights, the SpecterDR offers an optimized optical path and identical eye relief in both 4x and 1x modes. Depending on the situation, the user may adjust the sight to illuminate the entire crosshair or just a 1.5 MoA dot in the center. In 1x mode, the SpecterDR has by far the largest field of view in the industry. In 4x mode the SpecterDR offers a generous field of view, long eye relief, and ELCAN’s legendary crystal clear image. Situational awareness in both magnifications is improved with ultra-wide viewing angles and unmatched viewing in low light conditions. SpecterDR is half the weight and twice the capability of carrying two scopes, without compromise to mission effectiveness or reliability.

The SpecterDR offers the best single solution for both CQB and Long Range engagements and is designed to withstand the rigors of modern professional use.”

Source: https://cstactical.wordpress.com/2010/02/15/elcan-1-4x-specterdr-optical-sight/

Click .gif image to see animation of the red dot light settings.
Other images should give impressions too.