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Class Information
Number: 181/33HC
Name: Acoustics >

Sub-classes under this class:

Class Number Class Name Patents
181/ Speaking tubes 0
181/.5 Miscellaneous 98
181/101 Geophysical or subsurface exploration 51
181/123 Echo system 10
181/125 Sound location 17
181/126 Anatomic or prosthetic relation 27
181/138 Mechanical telephone 6
181/139 Wave generation and detection 30
181/140 With vessel 16
181/141 Combined 150
181/142 Wave generation 62
181/143 Moving sound producer or deflector 13
181/144 Plural diaphragm sound sources 254
181/148 Diaphragm and enclosure 256
181/157 Diaphragm 75
181/175 Sound-modifying means 160
181/30 Auditorium 74
181/400 Wave coupling 19
181/403 Refrigerator compresssor muffler 195
181/404 Hobby craft engine muffler 5

Patents under this class:

Patent Number Title Of Patent Date Issued

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