Thanks David. As I understand it (Sheldon posting many years ago) the single pin 10-3 are 440b and double ATS-34 stainless steel. 5 and 7 with 2 pin are also the 440b stainless. I know a lot more can be said as there are many variations and part of the fun of collecting them. And the 10-3s fill the miniature knife desire. In our state 4" is maximum for carry so that precludes carrying my 1-8
