RARE BRASS/COPPER MUSIC STAFF LINER (STAFF WRITER) in Manhattan, New York

A perfect item for that music collector.
An extremely rare and unique musical item. No other like it on the internet.
A music staff writer ? staff liner from the mid-forties/fifties.
Engraved:
BRUCE HUMPHRIES
PUBLISHERS
BOSTON, MASS
MADE IN U.S.A.
Comes with printed instructions (see photo)
Made of brass or copper or other heavy metal.