They are real vintage NOS tubes in original boxes made back in late 80s - early 90s in EI tube factory in Nis, Serbia. (Elektronska Industrija Nis)
If you like sound of Telefunken's smooth plates ECC83 12AX7, you'll like these too, because they are (almost) exact copy. The only differences are in thickness of halo getter and in "staples" which are facing each other.
You can find them rebranded Telefunken, Philips and Siemens, because all three factories had contracts with EI. These are pre war tubes, with exceptional quality, made with 1st class materials, because of that many of them have been rebranded like long life premium versions E83CC and sold by Siemens and Philips in their boxes.
You can also find them relabeled Telefunken with diamond mark on the bottom last few years! Diamond bottom mark is done on laser machine, and if you want to avoid that and to be sure that you are buying genuine Telefunken ECC83 12AX7, just take a look at getter and how staples are faced. Diamond bottom is not proof any more ...