I had an AKG C451B that was missing its mic clip. This was a perfect replacement. It matched my other AKG clips that came with mic exactly.
It can also be used with AKG D112.
There is no tightening mechanism, but the mic clip still retains its position perfectly. It is a softer, bendier plastic than the standard Shure clip, but then these AKG clips do not have to go through as much abuse as Shure clips. These are mainly used for recording and suite that role well.
My only complaint is with the price. For what is basically a piece of plastic, they are quite expensive. However, you really need this clip if you have C451 and D112 mics as they are a very specific size and nothing else will do the job.