The B-6037 is very interesting to me! This is because I have done extensive experimentation along the lines of making various hexadecimal readout systems
using nixie tubes. In my experiments, each HEX "digit" needed (2) regular 0-9 style tubes. The tubes would display 00 through 09, and then 10 through 15.
It is quite easy to use 10 through 15 as a way to visualize hex digits A through F. But using 2 tubes per digit is bulky and wasteful because the left tube just needs to show
0 and 1. But the B-6037 solves that! I never even knew such a tube existed. B-6037 must be quite rare. -Chuck