This is compound to put on a strop, to use as the last step when sharpening a knife. Not an ATL but not too bad, was $71 yesterday.
From what I've learned from youtube channel OUTDOORS55 this seems like a good choice, YMMV! Apparently diamond paste doesn't break down like chromium dioxide (the green stuff) and a good brand like DMT should in theory have a reasonable amount of particles in it. No personal experience yet with any of it but I'm giving it a shot.
If you know that you need only one size, single tubes are $35-40 with local shipping.
Regarding the different grits, DMT says:
Copper coded (6 micron / 4000 mesh) removes scratches with light pressure polishing action.
Yellow coded (3 micron / 8000 mesh) for a glossy bevel edge.
Gray coded (1 micron / 15000 mesh) for the ultimate polished mirror bevel edge.
Hmm DMT