Burris 300244 Speed Bead Sight For Beretta 391 Extrema 2 With the SpeedBead System, both the target and the red dot remain in focus. The optics and their position on the sight plane eliminate the need for perfect left/right, up/down head position for an accurate shot. The innovative mount puts the center of the optic directly in line with the ventilated rib, so altering your shooting style is not necessary. And with 3-1/2 inches to 4-1/2 inches of eye relief, there is absolutely no worry about your eyebrow running into the sight nor any interference with your hand gripping the shotgun.