Hi Guys This was part of my 50th Birthday presents and was from mom n pops. Im no expert but the item was purchased from very reputable dealer and its apparently one of the engine blades from a German WW2 Me 262 jet fighter either from the intake or turbine. The metal appears to be alloy and not steel but I was told early versions had alloy blades or sometimes a mix of alloy and steel for front row and back. The base has a threaded section as you can see from photo and the tip of the threaded piece has a number '21' stamped into it. There are no other markings on the blade. Its approx. 5-6 inch long but that's rough guess. Cheers, Tim.