Helmut Ryback

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Langenzersdorf, AT

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Patents Grantslast 30 patents

Information Patent Grant
Protective breathing mask having a speaking diaphragm for close com...
- Patent number 4,756,308
- Issue date Jul 12, 1988
- AKG Akustische u. Kino-Gerate Gesellschaft m.b.H.
- Helmut Ryback
- H04 - ELECTRIC COMMUNICATION TECHNIQUE