Anyone have a Wilson m-51 portable hardness tester?

[Signalprick]

Wondering in anyone has or is familiar with the Wilson portable M-51 hardness tester? If so can you help me identify what type of indenter this is? Sorry, this is the best pic I have. Thanks for any help!

 

[Signalprick]

Well I took a 50/50 chance on it! For $425 bucks I had to do it. I just received this M-51 and I lucked out! Diamond HRC indenter. It has 2 little spring loaded pins but they should not interfere in any way with testing blades and springs. Gotta get me a couple calibration blocks but I'm pretty dang happy to be able to do my own HRC testing in house.

 

[Signalprick]

And it works. That's an A2 spring I had tested at my buddies machine shop a couple weeks ago. He measured 48.5. I got 48.