Stated "extra capacity" and exactly the same height and circumference as the factory part number 12-050-01.
The only difference is 12-050-01 is black. It looks to be a factory part and not a knock-off. The KohlerEngines.com site says the 52-050-02S is a "premium filter", so maybe the difference is inside the casing, but in a side X side comparison they are identical except in color. I found the same filter at my local Kohler Power dealer for $ 7.89