Underground 660_T flash

Archived from groups: rec.photo.digital (More info?)

While cleaning an some old camera cases, I cam across an old flash unit
- Underground 660-T. Loaded some batteries in it and it appears to work
like a charm.

Unfortunately I cannot locate the instruction manual that it came with,
and cannot find anything about it with internet searches.

Does anyone know what the three slide settings (colored white, green,
and red) on the front are for?

Appreciate any information on this.

George