This an inexpensive copy of a Docter Optics sight. I have a Docter sight and like it pretty well.
http://www.opticsplanet.net/docter-red-dot-sight-third-gen-35-moa.html
It have used mine on a couple of my rifles for close range hunting. I can see where it would be fine for turkey and slug hunting, but for general shotgunning, I can't see a real use.