Actually there was some credibility to their document, although I can't locate it anymore, they must have pulled it. When the BS first arrived I ordered up a small handful of spinners and after reading the BM sheet, I thought what the hell and since I had an in at a military technical unit, I had the spinners measured up with their laser equipment. . . . the BM document was pretty well on. . . the BS spinners were no where near their aclaimed tolerances. . . let's face it, they claim in one document to have 100/50 & 100/75 etc. . the 100 being thousands of an inch wide and the 50 or 75 being in 10 millions (their website)of an inch deep, their tech sheet claims the 75 or 50 is in one hundred thousands. Give me a break! Unless you did as I did and have them measured up with laser technology, you will not know. I'm afraid your standard micrometer isnt going to cut it here! According to the military the spinners were plus/minus 25% Thats right TWENTY-FIVE % !! {largest tollerances found were in the depth} I have the spinners and use them when clients are eager for an FBV, but with the blade thickness differences, it is a real pain in the a$$ to set up each different pair to ensure centering on a spinner with a +/- 25% tolerance. I offer it to clients only if they insist. . .and caution that it is not near as accurate as acclaimed. These are the facts. I know it is the popular thing these days. People can be readily sold on almost anything. . . . I mean look at Bauer selling people the crap metal in their Lightspeed Pro holders...... some of those are like grinding plexiglass !