David M. Schaefer

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Downers Grove, IL, US

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Patents Grantslast 30 patents

Information Patent Grant
Isolating deep canal fitting earphone
- Patent number 7,477,756
- Issue date Jan 13, 2009
- Knowles Electronics, LLC
- Timothy K. Wickstrom
- H04 - ELECTRIC COMMUNICATION TECHNIQUE

Patents Applicationslast 30 patents

Information Patent Application
Isolating deep canal fitting earphone
- Publication number 20070217642
- Publication date Sep 20, 2007
- Knowles Electronics, LLC
- Timothy K. Wickstrom
- H04 - ELECTRIC COMMUNICATION TECHNIQUE