The biggest ones. I guess they're the 80s
They're best used on jigs that have the thin brass hook eye, like the old Ku-Jig Canal special type. Sometimes, certain brands of the Smilin' Bill heads have a very thick eye that makes using any kind of snap hard. If I have to use a jig like that, I tie direct with a loop knot.
Don't be misled by the thin appearance of those clips. I know guys who put incredible pressure on fish into the 40s in that honking current, and who have total confidence in that thing. I used them for the first time last season, all year, and they're still batting 1.000. No failures, not even a hint of damage.