Pu-erh tea

„Nèi fēi (内飞 or 內飛): A small ticket originally stuck on the tea cake but now usually embedded into the cake during pressing. It is usually used as proof, or a possible sign, to the authenticity of the tea. Some higher end pu'er cakes have more than one nèi fēi embedded in the cake. The ticket usually indicates the tea factory and brand.“

„Yunnan Provincial Government has stipulated that for tea to qualify as Pu er it must be:

i) of the Broad Leaf variety (Sinensis Assamica)
ii) grown in the Lancang (Mekong) River region
iii) sun dried. The third point is important as there is much tea grown in the Lancang River area that is not sun dried.

There are also increasing amounts of Small Leaf Variety (Xiao Ye Zhong /小叶种) being grown in the Lancang River area.“