I am the one selling these conicals. Here are the answers to your questions:
- Are they the same ones you have seen on E-bay before now? No.
- Would they be okay to brew in? Yes. I have had no issues at all with them. They work great. If you have specific concerns, please ask.
- Will they hold pressure? No. They are not designed to hold pressure. I would recommend using the conical for primary fermentation, and take advantage of the bottom outlet to drop out the trub and yeast. If you want to carbonate naturally, you could drain the beer into your corney keg and seal it up when the specific gravity gets to where you need it for natural carbonation.
- These conicals are a sanitary design. Sanitary valves, sanitary welds, no threads. They are not the same as "every other conical." They cost a little more as a result.
I'll be glad to answer any other questions you may have.
I am putting together a website that will have more information about them. When they are all ready, in about 3 or 4 weeks, I'll be shipping them to people who have contacted me through Craigslist or the website.
This website will have more information as I get it built out (it is still "under construction" so please excuse its look right now) - stainless steel homebrew conical fermenter.