This is the front sight only and is not easy to install. I had a GS remove the old sights so I had a clean slate to work with. I found the factory front sight had a groove cut directly down the center to accommodate the bump in the slide, which makes centering easy. The Trijicon has no groove, so I had to gently file, sand and align for a couple of hours to do the job right.
Now that the job is done I wasn't impressed by the level of brightness in dark rooms, but the big yellow circle makes getting on target (in normal/low light/most situations) real fast!!!!
I added Beretta target rear sights and the gun is dead-on @25 yds, with the ability to adjust for any situation.
Pros: Highly visible day and low light conditions.
Cons: Price for such a tiny front sight.
This review was written in the old system and had content requirements that are different than reviews written today.