wenbinbin2010
100+ Head-Fier
Hopefully this is just a general question and you are not considering buying from BangyBang. They are on the list of sellers to avoid:
https://www.head-fi.org/threads/over-priced-tubes.920115/post-16063045
I'm sure others have more experience with this question than I do, but I had the same question recently when looking at 12AU7 tubes, where there are many IEC and Mullard versions that seem to be the same, if not identical.
Oh definitely did not buy from BangyBang. Purchased a 5-pack of these IEC Mullard 12J5GTs for just around $40, almost the same as BangyBang's asking price for one tube.