This is a vintage Chouinard backpack in excellent condition.

And it is a beautiful pack.  A really stunning deep blue (with some purple), black, and red.  This pack has been used very little,  A true closet queen.

Not sure of the age but Patagonia was founded in 1973.  But, Chouinard did run more than one company for some time, and, as far as I can tell, Chouinard Equipment may have b been a viable entity until 1989.

There is one strap that has slightly frayed.  See photo.  And on the inside there is one spot where some coating that has started to flake.  Does not affect the structural integrity.

This pack is approximately 40 liters.  The rough measurements are 28"x14" x 8".