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Class Information
Number: 181/247.gtoreq.251
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 16
181/126 Anatomic or prosthetic relation 26
181/138 Mechanical telephone 6
181/139 Wave generation and detection 29
181/140 With vessel 16
181/141 Combined 149
181/142 Wave generation 61
181/143 Moving sound producer or deflector 13
181/144 Plural diaphragm sound sources 254
181/148 Diaphragm and enclosure 251
181/157 Diaphragm 75
181/175 Sound-modifying means 159
181/30 Auditorium 73
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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