Very rare, there are almost no mentions of this tester anywhere. Condition: the bridge is missing 2 vacuum tubes, see last photo. I do not know the numbers and there is no schematic inside that would give that information. However it's a pretty basic circuit and a competent repairman could hazard a guess as to which tubes would work. The main pot turns from the rear and that does turn the knob and the display in the front, but turning the knob from the front does...n't move the mechanism. I assume it's a wire/string reducing mechanism and it's slipping. The rest appears intact and functional but you may have to replace one or two components to restore. Displays very well as-is. Please see photos for condition. Will be carefully boxed for shipping, I have been selling since 1998 and my parcels arrive intact. I will send this overseas 'Surface' if you have decent feedback, but please know that it will take 30-45 days to arrive.