Hi All On the following picture http://img.photobucket.com/albums/v309/Andreii/ujj.jpg" [Broken], I have the tolerance Diameter 55 k5. Of course there is a big difference between k5 and K5 but that has nothing to do with my post. I would like to know why is exsactly this tolerance there? Why not, for example, Diameter 55 s3 or Diameter 55 j2 or Diameter 55 k4 and so on, why exsactly k5? So far I have got part of an answer but it does not help me. It might be because of this: http://www.skf.com/images/cat/images/1/1_0/017_0212.jpg The most lowest part of k5's red color is on the exact location from the 0 Line comparing to my piece of drawing but that makes no sense to me. There (on the SKF picture) are no Diameters given to ''read'' this k5. How can I see this, so microscopical small, length (between k5 and 0 Line) is correct comparing to the drawing? Tried to help myself with tables here: http://www.skf.com/portal/skf/home/products?lang=en&maincatalogue=1&newlink=1_0_76 but nothing so far... Along this, I would also like to ask two other subjects: http://img.photobucket.com/albums/v309/Andreii/trrr.jpg" [Broken]? Also, why are some of Ra's http://img.photobucket.com/albums/v309/Andreii/raji.jpg" [Broken] on the separated part of the drawing (in the top right corner) - some of them are also in brackets, why? Hopefully we could figure that out. Thank you for the reply.