Granted Patent
Utility
US 6,327,902 · App. 09/344,737
Air filter restriction indicator gauge
Inventors:
Charles Henry Berry, III, Gregory Matthew Ferris
Patented Case
View Patent ↗
Granted: Dec 11, 2001
Filed: Jun 25, 1999
Inventors
Charles Henry Berry, III
Gregory Matthew Ferris
Assignee (at issue)
Engineered Products Company
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.