Is this the one...
And does co-witness mean that irons sights line up with the eotech dot ?? If so, how is it that they line right up? Or does co-witness just mean you can look through the optical sight to see the front sight... sorry.. new to all this. And, do I just mount this on my rail and it is lined up OK with the height of the EOtech which is also on the rail? I have the 517, which I think is 7mm higher than the 512.