Practical thing funitioniert, excellent and - above all - is always there, because very handy and very well protected inside a transport bag. I have no experience with gray card, but with this cube is the white balance in RAW Converter breeze. Mainly because the different sides of the cube are always either in the light or in the shade and therefore a subsequent Weiss (gray, black) allow adjustment in any case (in highlights or shadows). Very good also the "black case" - blacker than a hollow body with black walls gehtŽs not. Bin, even if that thing is a little expensive very satisfied. Important in this context, however: the monitor should already be color calibrated, eg with the SpyderPRO.
