This is one of favorites from my collection of factory knives. Case made the M-1 survival knife for NASA and these were carried on every manned Apollo and Gemini space flight. One went to the moon with Neil Armstrong. They chose a big survival knife because in those days the space capsule returned to earth by parachute and there was a possibility that it might land in a remote area or jungle. It is 17" long overall and has a 11 3/4" blade. It features white polypropolene handles (the lightest plastic that gives off no toxic fumes in case of a fire) and saw teeth along the back of the blade. Case made 2,494 of the knives for sale to the public at $75.00 each between 1966 and 1972. In 1983 Case produced a special "2nd run" of 1000 knives commemorating NASA's 25th anniversary. The anniversary knife is identical to the original M-1 except that the blade has been etched with a special color logo.