What does that box do on MIT cables?

I know a lot of high end home audio companies do this , but MIT is probably the most famous. What does (if anything) the boxes do on MIT rca cables?
I didn't find the right solution from the internet.
References:
http://www.diymobileaudio.com/forum/car-audio-truth-myths-industry-dogma/342818-what-does-box-do-mit-cables.html
infographic video