1551-C Sound Level Meter General Radio Company Tested working

General Radio Company Sound Level Meter Type 1551-C

General Radio 1933 Precision Sound Level Meter & Analyzer (UNTESTED)

GENERAL RADIO COMPANY 1551-C SOUND LEVEL METER w/ 1560-P5 MICROPHONE

General Radio 1551-C Sound Level Meter with 1971-9605 Mic and Case - Lab Tested

1950s General Radio Company Type 1551-C Sound Level Meter Vintage Original '50s

GenRad General Radio 1565-A Sound Level Meter w/ Leather Case – Untested Vintage

GENERAL RADIO COMPANY 1551-B SOUND LEVEL METER no power supply