Schwinn never took advantage of their position in the early mountain bike market.  Most of the early mountain bikes were based on the early Schwinn balloon-tire bikes from the 1930's and 1940's.  This was their attempt at a mountain bike.  Remember that this was the first year of the Specialized Stumpjumper and Schwinn was offering a Varsity frame (looks like filet brazed but it is Electro-Forged) with BMX parts.  It took them several years to realize that mountain bikes weren't going away and make a more serious off-road bike.  This example is in near pristine condition with all original parts except for the seat.