David M. Campbell II

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Johnson City, TN, US

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Patents Grantslast 30 patents

Information Patent Grant
Earplug shaper having curved shaping surfaces
- Patent number 8,870,558
- Issue date Oct 28, 2014
- Daniel R. Schumaier
- A61 - MEDICAL OR VETERINARY SCIENCE HYGIENE
Information Patent Grant
Hearing aid apparatus
- Patent number 8,718,307
- Issue date May 6, 2014
- Daniel R. Schumaier
- H04 - ELECTRIC COMMUNICATION TECHNIQUE
Information Patent Grant
Preprogrammed hearing assistance device with audiometric testing ca...
- Patent number 8,472,634
- Issue date Jun 25, 2013
- Daniel R. Schumaier
- H04 - ELECTRIC COMMUNICATION TECHNIQUE