These are some of the earliest Bach mutes that I have ever seen. It is labeled as:
MASTER MUTE
V.B.C.
TRADEMARK
Vincent Bach Corp.
237 East 41st Street New York
These mutes would date from the period of 1922 to 1928, based upon the factory address above. Vincent Bach had these manufactured by Joseph Rapuano at 222 East 105th street, New York City, NY who was building mutes and assembling French Besson “Fabrication” trumpets at this same time. Joseph Rapuano earlier in his career was the 2nd trumpet, Metropolitan Opera Company of Chicago. (reference)
Master Mute
V.B.C. Trade Mark
Vincent Bach Corp.
237 East 41st Street New York
Trumpet model (from Chris Dankler collection)
Master Mute
V.B.C. Trade Mark
Vincent Bach Corp.
237 East 41st Street New York
Trombone model (from the BachLoyalist collection)
From the 1925 Vincent Bach Corporation catalog (page 17).
Source: Chris Dankler, photo of Master Mute (trumpet); BachLoyalist collection, Master Mute (trombone)