This is a Tektronix TM515 portable main frame with FG504  function generator with sweep option, and an AA 501 distortion analyzer module along with a DM501 A digital multimeter module. I do not have the front cover for this. I have tested it and it seems to work OK I haven’t dived too deep in seeing if every feature works as it should, I’m sure it needs calibrated so therefore it is being sold as is.