Product review (5 stars): Not a 38/400 thread pattern like real growlers!
Update: The seller contacted my and went above and beyond to correct the error, changing the listing and shipping me a replacement product for free. If you are okay with the thread pattern this growler will work well for you. Hopefully someone will build a carbonating cap for it in the near future. If they do I'll buy this again because honestly the thread pattern would be better for carbonating than the standard 38/400.

Here is my previous review: It is a single walled stainless bottle, so no insulation to keep the contents cold. While it does look small it holds 64 oz, but with no head space. It has one critical flaw for people interested in using it as a growler though: the thread size of the cap is non-standard! The standard growler thread pattern is 38/400 while this one has some metric thread I've never come across. The lid diameter is indeed 38 mm but a standard growler cap won't fit as the thread pattern is much too fine. I had planned to carbonate in this growler using a 38/400 carbonation cap and Das Beer clearly answers a customer question posted above about the cap size saying it is 38 mm. Either they are deliberately trying to mislead customers (unlikely) or they just don't know much about home brewing beer in America. The manufacturer is likely a Chinese company that just received an order for bottles with a 38 mm cap and they just used their normal metric thread pitch rather than considering the end user. The growler seems to be constructed well and if you are just going to use it as a water bottle you should be fine, just don't lose the cap!