PAT 143526 21cm Spanish OTF DA Black & Aluminum Automatic knife

Vintage PAT 143526 21cm Spanish OTF DA (Out the Front Double Action) Black & Aluminum Automatic knife most likely made in the 1970s. It measures 21.1cm (8 3/8 inches) open and 4 7/8 inches closed with aluminum frame and plastic scales & button. The flat grind spear blade is full and shiny with light scratches and the tang is stamped with what appears to be PAT over 143526. The checkered black plastic scales are in very nice condition with no shrinkage. The knife works great with blade opening fully and locking when the button is pushed forward and retracts fully into the knife when the button is pulled back. EX condition.