Many thanks to SWLing Post contributor, Rich Stahl (WR3V), who writes:
Rare as hens teeth, and said to be excellent units. Looks to be in nice condition.
I’m not that familiar wit the Muzuho SX-3, but it does appear to be a quality unit and has great reviews. Preselectors can be incredibly useful to radio enthusiasts who live in the presence of blowtorch signals or who have sensitive receivers that can easily overload. Thanks for the tip, Rich!