YEs I have used one but recently sold it. Depending on your setup it may or may not work. IN my case, it worked OK with my fixed 4 power scope, but with a variable it did not work because the power adjustment ring hit the peep and there was not enough clearance. One size most definitely does not fit all.
It is windage and elevation adjustable. There is a very small spring kind of captured that pushes the peep up. I changed to a Talley and of course that begins the new problem of finding a good place to store the peep when not in use, but I like it better overall.
I would suggest doing some measurements with your ring etc first... I used Talley rings in custom bases by MArk Stratton. The ring spacing is wider than I wanted and I think that was most of the issue, still, don;t assume it will just work first out of the chute.
