Granted Patent
Utility
US 5,203,352 · App. 07/598,268
Polymeric foam earplug
Inventor:
Ross Gardner, Jr.
Patented Case
View Patent ↗
Granted: Apr 20, 1993
Filed: Oct 16, 1990
Inventor
Ross Gardner, Jr.
Assignee (at issue)
Cabot Safety Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.