The #40L SP is identical to the #40L but it utilizes our same plane aperture system. This aperture set allows the operator to choose between large and small apertures without worrying about them being zeroed to different ranges. The #40L always deploys with the small peep (250-300m) aperture as primary. To switch to the large peep (close quarters) aperture, simply flip the small peep down. This sight is for the competition shooter. The Small aperture can also be removed if the user desires the larger CQB aperture only. Windage is adjustable in .75 MOA increments. The low profile #40L will fit under most traditional powered optics and other configurations where the #40 or #40A2 would be too high.