That looks like a clone of the Kerr Electromelt or Maximelt furnace (it's a furnace, not a "smelter;" smelting is the process of extracting a mineral/metal from ore). Probably uses the same crucibles as the Kerr units. Could be 1, 2, or 3 kilo. Hard to tell from the picture. The Kerr units are of good quality, I don't know much about the clones.
Crucible is easy to replace and relatively cheap. You'll want a separate crucible for each metal to avoid cross-contamination anyway. The real question should be the condition of the heating element and the interior refractory. That's the expensive part to replace (if parts are even available separately for these imported units, again I don't know).
The heating element will wear out faster melting copper because you'll be running it at the maximum temperature.
I have two lightly-used Kerr MaxiMelts (3 kg). The first I paid around $750 for, the second was a total steal at around $250. If it's truly equivalent to a Kerr furnace, $600 is a pretty fair price.
This place has a package for $500 shipped. Again, no idea of the quality.
www.ebay.com/itm/320947792722