"Postal Padlocks - United States - Rotary"
The following symbols have been seen on the shackles of some locks: ★ ⊖ ▲. To help in discovering the meaning of the symbols we are maintaining a shackle symbol table.
We have ruled out that the symbols represent the manufacture because the early Smith & Egge locks and the later Mail Equipment Shop locks bear the same symbols.
Cast Brass Case Stamped Brass Case