In my ongoing research on Herman Conrad (1867-1920), I learned that at some point Frank Holton made a "Conrad Model" tuba mouthpiece. Don Harry let me know about this, as he has one of these in his collection:
On the other side of the mouthpiece it says "Frank Holton, Chicago," which means that it was produced prior to the Spring of 1918, as that is when Holton moved his business from Chicago to Elkhorn, WI.
From 1903 until he passed in 1920, Conrad was part of the elite group of musicians who were the "house band" at the Victor Talking Machine Company, and this mouthpiece probably came out during those Victor years. He was playing Holton tubas during much (and possibly all) of that time, so it's not surprising to see a Holton mouthpiece bearing the great bass player's name.
What is most curious is that the rim is concave, which I'm thinking is something that Conrad preferred (although Holton made a whole line of concave rim mouthpieces, starting at around 1911). According to Don, "the concave shape went horizontally for a very narrow jaw formation." Here's the Conrad Model next to a more standard Holton mouthpiece:
At this point, I am not aware of another copy of this mouthpiece existing - nor have I been able to find any notice of it in a Holton publication from that era (although, granted, I don't have access to everything they produced during those years).
But I would imagine that calling it a "Conrad Model" was a nod to Conrad's fame as a tubist in the early 20th century (and perhaps a way to sell more mouthpieces?!). Conn had his "Helleberg Model" bass mouthpiece around that time, and Holton had his "Conrad Model." Two giants of that era!