Who sells check valves / flash back preventers like these =>?

Question

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=180265591744

Answer 1

any kind of equipment that can be used to operate anything that is electrically connected then you can go to a hardware store and/or any electrician or gas company to get the parts if if the electrician or hardware store does not have it if it is any kind of valve or regulators or pipes.

Answer 2

Um, there is someone on Ebay ?

You might try a laboratory supply company for things that size, would probably wont find them at a hardware store.

Back flow preventers for welding are available at (surprise) welling equipment suppliers, but they are different that what you linked to.