Frequency Meter 119 0 Download here USA110 - US1402025 Print Rate this article: No rating No.USA110Patent1,402,025Year1922CountryUnited States of AmericaDate of ApplicationJanuary 3, 1922Patent TitleFrequency Meter Documents to download USA110 - US1402025 (.pdf, 313.98 KB) - 97 download(s)