That thing is going to sell like MAD and rightfully so, it is an excellent design. I mean, superb. That whole series from Polkowski and Kasper's Large KFF from Crawford are simply great Self-defense tools.
I think for $50.00, anyone serious about Self-defense could get three of them, two for carry and one to dull and round off to train with. That way you have a sheathed trainer that is identical.
You need a grinder, an extra coarse Mill Bastard File and a whetstone and some sweat to get one to where it is not dangerous though.
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"You are no more armed because you are wearing a pistol than you are a musician because you own a guitar." ~Jeff Cooper
And the same goes for a knife...
And, I'm a Usual Suspect.