Alumina Intensifier YL (Yellow) cuts blue light that is predominant in dusty, hazy conditions. You'll see sharper details and brighter, better defined images. It also brightens a dull image on a cloudy day and darkens soft gray shadows for better contrast. The Intensifier YL also eliminates the violet and blue light rays seen in a halo at the edge of black areas of a target. You'll see a crisp black edge of both target outlines and bullet holes in paper. It even makes game animals easier to spot from cover on bright and hazy days.