In the tea industry, tea leaf grading is the process of evaluating products based on the quality and condition of the tea leaves themselves. The highest grades are referred to as OP or, "orange pekoe", and the lowest as "tannings" or "dust". 

From this OP, we have FOP, which stands for Flowery Orange Pekoe. In this case Flowery denotes the large tea leaves, which are typically plucked from new shoots and consist of two leaves and a bud.

Next better level of OP is GFOP, which stands for Golden Flowery Orange Pekoe. In this case Goldenrefers to the golden tip, the very end of the golden tea buds.

Following level is TGFOP, which stands for Tippy Golden Flowery Orange Pekoe. Here Tippy refers to the amount of golden tip in the tea. Such tea will typically contain a large proportion of golden tips.

And finally we have reached FTGFOP, which stands for Finest Tippy Golden Flowery Orange Pekoe. Finest in this case refers to the fact that this tea really is the finest. Only teas of exceptional quality will have this grade.

But it's not finished yet, SFTGFOP which stands for Special Finest Tippy Golden Flowery Orange Pekoe. Special stands for the fact that a tea with this classification is truly unique and very rare indeed. Sometimes this will be prefixed with number 1 indicating that particular tea as being even more special, so the grading would be SFTGFOP1