In the late 1990s the internal recipe codes of the largest puerh factory, Menghai, became public knowledge and many of the new smaller factories that were open wanted to try their hand at making these famous recipes of old. These generic recipe cakes are now very affordable and clean, as there were little to no agrochemicals in Yunnan in the late 1990s.
The factory codes are broken into three parts. The "75" is the year the recipe began (not this cake but the blend); the "4" is the average leaf size (1 to 9, so rather small in this case); and the "2" represents Menghai factory (there weren't many factories in those days, so single digits would do.
7542 is an excellent tea to drink now with a strong and bright liquor. The storage on this cake is clean. It can be aged or enjoyed now. This is a beautiful cake, indeed.