In a thread a few months(may or june) ago about BUIS’s somebody had posted a link to Diamond Head Sights(www.diamondheaddesigns.com). I found out they were only a few miles from me so I contacted them about picking up one of their sights to test out. They told me at the time they would not be available until August. I just emailed them again yesterday and they told me they are fully up and running with their sights now. I am going to order one and will post up some results when I get it and have a chance to go shoot with it. I am only going to be getting the rear flip up as I have a standard FSB on the front of my DD M4.