OK, everybody has posted this it seems and this is yet another. But, I have never had sights that literally just fall through the rear dovetail like these did. I did notice a little more play than I would like in the front sight. It tended to move left / right, so make sure you use a little straight edge to line up against slide lines and get it straight. Definitely degrease like they say. THe rear sight, as I said, pushed in with no resistance and then could slide right out the other side. Maybe this is new due to so many being broken during install without fitting properly 1st. I put a drop in the dovetail and then slid sight in. Lightly tightened the set screws to gain some friction and then centered. Used the Dial caliper depth guage to get it centered and set the screws. Check it again as it does move a bit when screws are tightened. Added plenty of locktite and let it set up. Then cleaned residual away. Video makes them seem easy and actual install is even easier. Once I go to the range, I'll find out how I like them, but so far they produce a nice sight picture and very bright. My only question is: XS says NO locktite in set screws and it seems logical so you can still adjust. Another persons instructions say to fill them up so they never come back off. My thought is when they are sighted in and found to be proper, is it best to seal the setscrews in to reduce your chance of them falling off? Or do they stay put with the setscrews? In my experience with working on guns over the years, setcrews tend to work out due to vibration. But I have worked on guns where the factory filled in the setscrews with red locktite and it takes an act of god to get them cleaned out and remove for replacement of parts. But they definitely don't come out on their own. Nothing more frustrating than having sights or optics loosen. I do love these sights so far. Shooting will tell if love affair is just a flash in the pants or long term true love.