From what I've read it doesn't fit. TheTomas measured the Preon at .429" so the Dark Sucks clip would have to be bored out and would leave only .043".
http://edcforums.com/threads/preon-2-clip-replacement.88209/
I can't see how it would be that difficult to ream out the clip to fit?
I might try it but I have 2 preon and I am just not as crazy about them as I was at first.
The switch just sucks to me.