They fit under an ACOG. They only flip up on their own when they get wore out. They still suck but I have a set.
http://i851.photobucket.com/albums/a...ps2d7e4b3b.jpg
I like the Troys the best for flips and Daniel Defense for fixed.
I dislike the KAC sights. Who seriously needs their back up sight to have a big ass windage knob or be elevation adjustable out to 600M?

