Basically just a clamp on the barrel fiber optic made by HiViz (I think, maybe TruGlo). Snaps on to the rear of the bead. It's a nice bright dot. Only problem is when shooting a class recently, I was shooting a round of slugs at 25 yards, I found it to shoot about 2" high. After further looking I realized it was half a bead lower then the factory installed bead. So it made me shoot a touch high. With buck shot, and really slugs too, it's not a huge deal. But something to mention. You want it? Come get it. I don't think I put it back on. I think I'll be drilling out the silver bead, and tapping it for a screw in replacement. I'll be doing the same with the black one too.