[Linked Image from i.imgur.com]

The script »RS« is going to be the tubeset knitters stamp of liability & compensation. The other pink encircled mark is that of a tube maker that converted Belgian sourced rough bored tubes from Bar Stock to a barrel.

I think tube mechanic Robert Schlegelmilch passed in 1924, so he may be out of the running.

Hochachtungsvoll,

Raimey
rse