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.“

„cha qi; 茶气 - Tea nature. The inherent energetic qualities in tea. That which makes it tea. Sometimes rather unsatisfactorily interpreted as 'tea energy'; translating qi as energy suggests perhaps a rather too narrow idea of qi but it is an interesting term to consider since many people use the term. Ideas and experiences of cha qi vary considerably; the taste of tea, the appearance of the leaves (particularly after steeping i.e. the life in the tea), any physical or psychological experiences one may have as a result of drinking tea are all aspects of cha qi. One cannot satisfactorily dissociate one from the other just as one cannot isolate sunshine from wind, which are both manifestations of weather, tian qi. If it did not have cha qi it wouldn't be tea, it would be something else. From a western point of view perhaps, cha qi is due, in some good part, to the presence of caffeine, theine, etc. The active constituents.“