Compact back-up sight - Ruger Top Mounted Deployable Iron Sight

This is the second one I've bought. Its compact and I like that its just one peep-hole, straight forward. Co-witnessed with my red dot scope, and it looks great. I think its more compact compared to the Magpul sight. The knob is also tight, so there is no concern about accidentally moving it. If you do move it, there are vertical lines indicator on the back, so you can tell if it had moved left or right. After I have sighted mine in, I marked it.