INOX BREVETTATO 21cm Italian OTF Trapdoor 1960s Aluminum automatic knife

Vintage INOX BREVETTATO 21cm Italian Trapdoor Checkered Aluminum automatic knife made in Italy by Rosa Uliana Primo in the 1960s. It measures 21.3cm (8 3/8 inches) open and 4 7/8 inches closed with nickel silver button and safety. The flat grind swedge blade is 99% full or better with nearly all of the original finish and some light scratches and is stamped INOX on the ricasso and BREVETTATO on the reverse. The aluminum checkered frame is in very good condition and both sides have a nice checkered crosshatch pattern for better grip. The trapdoor is hinged on the left side  unlike most of the horn versions that are hinged on the right side. The knife works well with blade tip flush with end of knife closed, opens fully most of the time and locks when button pressed. Press button again to release blade to be closed and then cocked into firing position with hinged trapdoor. Sometimes these are a little finicky and takes more than one push of the trapdoor to cock the knife or held at just the right angle for optimum operation. Also best to move trapdoor out of the way before opening and hold knife level, or pointed down for best open. EX condition.