The Kohler Cimarron toilet is a low flow Two-Piece toilet. This toilet has more of a streamlined look than most toilets. Usually to tell the difference between a Class 5 and the Class 6 is to look at the trapway outline, if the "foot" outline is clearly visible, it's a Class 5, if the bottom half outline isn't noticable, it's a Class 6.
First Gen (2004-2007?)
This gen doesn't have much difference with the new gen other than having a different bowl with the Class 5 flush. It has a single spout at the bottom of the bowl pointing straight, a weird tank, and a "foot" trapway opening. Like most modern low flows, it offers a straight down flush. This originally ran on a regular flapper until it got replaced by the AquaPiston Canister around the Late 2000's, and was used with the Later Class 6 models. The two piece model with this flush is discontinued, but they have a one piece model with this flush that is still made today.
Second Gen (2006-Present)