ARS Tubes

i pulled the original drive tubes from my VTL MB 185 to do some tube-rolling. The original tubes are labeled as ARS -- "since 1947". I've not been able to find any info on this brand of tubes. I'm sure it's because I'm new at this and "ARS" is probably code for some other manufacture, but it would be interesting to me to know the actual details. Thanks for your help.