TCGC-2KM Autotransformer Inside Look
Chinese 20 Amp Autotransformer
Soldered connections are (of course) done with Lead Free Solder. Does not hurt to examine them! Don't look for shiny connections, because Lead Free Solder always looks dull.
Windings look very well done.
Wiper assembly looks to be very sturdy, and the brush looks easy to change if necessary.