Veering away from the subject a bit, I saw for the first time a sign with maximum container size of 3.4. at STL airport. I didn't understand, so I Googled and found this web site.

Does anyone know where 100 ml size containers of toothpaste, shampoo and shaving cream can be found? I know smaller sizes exist, I have them already, but if 100 ml is a standard size outside the US, they're probably available via the web. And is there an official posted guideline on the 100 ml volume (tsa.gov?) that I can print out and carry if I need to convince a TSO or supervisor?