I use a 3d rda; it threads to m20x0.5
so it fits on nemesis;
technically it can fit on my poldiacs but the podiac's a topfired, so doesn't exactly work out without some moddng.
then there is the elm rda which fits on the treeoflife mod;
I dont' remember if it's m20x1 or,,,, that's gotta be...