Branch Immaterial - explanation

[cz_raf]

Hi,

while researching bio of one American soldier I have found he was posted into Branch Immaterial - Warrant Officers, USA.

As English is not my native language can anybody explain me what branch he was serving with?

TIA

Pavel

[fsbofk]

This may help explain what Branch Immaterial means: http://fotw.fivestarflags.com/us%5Eartbi.html

[cz_raf]

Thanks for help!