Trying to figure out Sage Click reels. I just obtained a "Click 0/1/2" (already have a 3100) and trying to figure out how many times Sage has changed this reel. I see there's a Click II, and that the spool has an "S" on it, so it's obviously different from the current Click. Was there a Click I? Click III, etc.?
Any help is appreciated.

That’s correct. The numbers are like Orvis CFOs or Battenkills—sizes I, II, III, etc. As to the generations of Sage Click series reels, I believe they evolved from the 3000 series (3100, 3200, etc), and there has been one update since the original Clicks. I think the only changes were in colors and porting designs. Sizes and weights remained the same. The 3000 and Click series owe a lot of their concept and “drag” design to the original Waterworks Purist reels. Wychwood River & Stream reels also borrow heavily on the Purist.

The current edition of Click reels is sized by recommended line weight range (0-2, 3-5, 4-6). The previous edition is sized I,II, III. You can assume that the old size I equates to 0-2, etc. I suspect Sage changed the numbering system to make it clearer what the recommended lines are. Obviously, to me, they just added to the confusion.

Your Click II is the next size up in the series. I don’t know who would limit it to a 2wt line. That could have been because when the Click I, II, III were current, Sage sold 000, 00, and 00 lines and rods, and they wanted to differentiate which reels they intended for which rods, or to sell people more reels if they bought, for instance, a 000 wt rod and a 2 wt rod. In reality, one reel with one extra spool would have sufficed.

Now, to muddy the waters even more, a 3100, or Click I, or 0-2 (for example) can easily hold a WF3 line and enough backing for pretty much any small-average freshwater fish. If you use double taper lines and cut them in half, as many small stream and UL anglers do, you could likely fit half of a DT4 on a Click I reel with more backing than you’ll ever need. Some people like to get the smallest reels that will hold their line—for aesthetics as well as lighter weight on light rods. There are no rules, so long as your line fits without jamming.

Yes, and the line ratings for each appear to have been more aligned with what UL line wt rods Sage offered at the time than what actually fits on the reels.