Dust, It's just a 1moa dot in the middle of a circle... the dot is the only portion that is illuminated,
On 2x, it's a really fast scope and your eye tends to really put the target in the center quickly...the dot allows for some decent precision shooting when you take it to 7x..
I think it was originally designed for shotguns and can be used for a range finder, much as the mil dot scopes, without all the clutter. I've used it on my AR in a couple of competitions where the targets were bowling pins at 100 yds and hanging 8" steel plates at 200+ yds and found it to be faster than the old Leupold Rifleman 2-7x that I used to have..
