I would be interested in one of these… but only in the default/traditional Stanley Green. Call me square, but I really do prefer to run unobtrusively stock, at least from a visual perspective. If I get one, it will be purely for the quality of it’s build and it’s functional attributes. I wouldn’t even care to be noticeably seen with one, I would just care that it works and fulfils its functions in an exemplary manner.
45$ is way too expensive - I can't figure out why Stanley and Hydro Flask are on the expensive range. 25$ is more than enough for a high-quality vacuum thermo-flask. I got myself two 1l bottle from Borosil for about 755₹ (9$) per bottle. It's been more than six years, there's a few dents and scratches, but it works just fine.
I got myself a Milton Aura 750 ml last week for ₹850 offline, great. Does Borosil not get rust on the top end where cap screws? I saw many Amazon 1 star complaints with photos.
Are you talking about the Borosil Hydra Bolt? Then no. The cap suffers from deformity, but that's it. There is no issue with the body, and it still performs really well in containing the heat.
Apparently, almost all mass-produced bottles have lead-based solder in them, including the expensive ones. Lead-free solder is expensive, so there's not a lot if brand that exists with safe solder. Also, the solder dot is on the outside, at the bottom of the flask, so as long as it is protected from erosion by use of a cap-like structure, you're safe.
Updated my old comment. Lead is present as a solder dot in most of the expensive flasks, including the Stanley. Mine happens to have a cap over the sealed area. My particular flask is made of stainless steel grade 304.