I wouldn't feel too superior about it; it's blatantly ripped off from custom condom sizing.
http://www.theyfit.co.uk/pages/about-theyfit
The numbers and letters of the sizes are randomized so that guys don't feel ashamed about their dick size.
http://www.theyfit.co.uk/pages/about-theyfit
The numbers and letters of the sizes are randomized so that guys don't feel ashamed about their dick size.