Here’s the A.R.M.S flip up rear sight, which I use on my AR-15. A few things first off that are obvious would be that it is metal, so it will take a bit of abuse if knocked around. Also it just screws onto your rail system like most other attachments or accessories, just use the allen screw it comes with. The little metal arm on the right side is what holds it down, push that back and it will flip up. It can be a pain in the behind sometimes trying to get it to lock down, because its not just a simple push down, and its locked in (push the arm toward you and push your sight down). It’s not difficult but can be annoying when you are trying to hurry to lock it down. The good thing with that is… I have found it doesn’t accidentally pop up if say its in my drag bag on the way to the range or maybe it gets caught on something. The adjusting knob on the left side is to make left and right adjustments only. When sighting it in it only took a few rounds at 50 yards and then after that it was pretty much spot on for shooting at 100 yards. I did find the sight picture on this to be very clear compared to my last rear back up sight. I’ve never shot with the ghost sights on this but looking through them they look great. Price wise this was over $100, but with that being said I am very happy with it and do not see myself replacing it anytime soon. I have an A-post iron sight in the front… Hope this helps if your looking for a rear flip sight.