Sun CVT-260 Co2 Timing and vacuum analyser

[abl567]

Vintage engine analyser by Sun Electric (Nederland) I used this often tuning the MFI for the 6.3
Worked perfectly last time I used it probably 3 or 4 years ago.
I'm asking $450 but have no real idea of value, it's clearly rare as a google search comes up blank.
Offers invited