The letter FT indicates that the product was customized and reimbursed by Taiwan Province Toffee Company. 86 in 8603 represents the formula formed in 1986, and 0 doesn't know what it means. According to the normal label, there should be no 0 here, but a number like 1-9, indicating the grade of raw materials used in Pu 'er tea. The last number, 3, represents the output of Xiaguan Tea Factory. Regarding the last number, 1 stands for Kunming Tea Factory, which was an enterprise of China Tea Company a few years ago, 2 stands for Menghai Tea Factory, and now it is an enterprise of Dayi Group, 3 stands for Xiaguan Tea Factory and 4 stands for Pu 'er Tea Group.