As stated on the cover..." Operating and service manual, model HP 333A/334A Distortion Analyzer.
For: Serial #'s 333A: 1137A03146 & greater 334A: 1140A05641 & greater
Dated 8 June 1976
Email me with any questions.
Asking $30.00USD + shipping
cowboy67atcasscommdotcom at=@ dot=.