Here is a handy piece of test equipment for the audio techs.  This is a Hewlett-Packard model 331A distortion analyzer.  I am selling it as is untested.  The power cord is missing.  It looks like a standard computer type power cord.  The unit is in very good condition and probably works fine with a new power cord.  I am selling it cheap because I can't test it.  It measures about 17" X 13" X 6"