Hδ line for a number of B3 stars illustrates our criterion for assigning luminosity class. We note that the B3 II star is much closer to the supergiants than to the giant standard. The only fast rotator in the set is the B3 V standard η UMa. Its profile is drawn with a thicker line, as high rotational velocity modifies its shape so importantly that it crosses the lines for higher luminosity standards.