I've noticed the same problem with the P-51.

BTW, I have 2 of the little sharpeners, one in my camping gear, 1 in my BOB. I just broke one out today and it worked great! Touched up my S30V blade in a few strokes. About 20 strokes on each side to get one of my 440 blades back to near-shaving sharp.

Now,before you think it, NO, I'm not really outstanding at blade sharpening! So I'm pretty happy. I wish I could find this stone in a bigger, kitchen, size.

I've got the Diplomat too, but from a different vendor. Not a bad item. I use it to keep some odds and ends in my backpack for when I spend the night at the hospital. Contact case, eyedrops, my inhaler (you never know), toothbrush, paste, spare change, padlock for locker. it's too crowded for belt wear (and kind of big), but it's great at keeping stuff in one place.