Mounted it to the gas block picatinny rail on my AR-15. It seems to be a lot more stable mounted there as compared with front sights that mount on the top rail. Glows sufficiently bright in the dark and is great for daytime usage too. I really like the HK shape, it is a lot easier and quicker to get the sight aligned with the rear peep sight than it is with the standard shaped AR-15 front sight configuration.
Pros: Very stable, can see well under low light conditions
This review was written in the old system and had content requirements that are different than reviews written today.