The MATechs are junk. .
They pop up when dragged against gear and the range lever will get knocked down to the 600 setting with the same treatment.
They don't lock up or down.
I know they come on all new Colt M4A1s, but I really don't like them.
I much prefer the Troy flip up rear sight which lock up, are difficult to knock the windage adjustment off, and offer both aperatures. Cost is a turn off, though.
I'm with the chorus on this though: use a fixed rear sight if you are only going to use irons as flip ups are best if used as backups.
God gave you a soul.
Your parents, a body.
Your country, a rifle.
Keep all of them clean.