Admission is free.
The John M. Mossman Lock Collection constitutes the main exhibit within the museum of the General Society of Mechanics and Tradesmen. This collection represents one of the most complete anthologies of locks in the United States. Here, more than 370 examples trace the history of the lock, from ancient wooden locks, four thousand years old, to modern 20th-century time locks. The collection is highly specialized, featuring primarily bank and vault locks. Nearly every lock in this collection has protected untold millions in money and securities.