I'll be the first to admit that I am a pretty impatient person. Although I'm still in for one of each mount with the group buy, I picked one of the RMR mounts up retail. If you are on the fence, hop off and get one (or more) of these. I can't imagine a better solution for putting a reflex sight on an MP5 without adding a lot of bulk and weight. The top of the RMR is only about as high as the top of the front sight ring. The weapon is essentially no bigger than it was before, and that's especially important to me with the K guns. The sight appears to absolute co-witness with the front sight post although I have not been out to zero the dot -- at any rate it will be very close. Here's some more pics -- bonus points for anyone who can identify the blurry object in the sight picture photo. Oicani, I hope it's ok I put these pics in here.