Mando-basses are tuned like a double bass, (EADG, low to high) and resemble them, except they're pear shaped, have frets, and round sound holes. Ok, so they're nothing like a double bass. Gibson (and others?) manufactured them back in the good old days, sort of preticessors (SP?) to today's acoustic guitar basses. I heard of one recently bringing $2 grand at a show in Philly, but those that still exist are mostly in rough shape. The gutair and amp shop in Harrisonburg, VA (inches off interstate 81) has two of them, but the guy is a collector, mostly of tipples and ukes, and doesn't seem anxious to sell. Pretty cool axes, though...