Granted Patent
Utility
US 4,193,396 · App. 05/900,982
Paired earplug construction
Inventor:
Albert R. Wacker
Patented Case
View Patent ↗
Granted: Mar 18, 1980
Filed: Apr 28, 1978
Inventor
Albert R. Wacker
Assignee (at issue)
E-A-R 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.