I'm not being a smarty pants - but have you looked on their website? I seem to remember they have a whole section on the different bits and their actions.
I bought one last week which arrived Friday. Hacked out in it Friday and couldn't find any difference in her TBH and was mightily disappointed.
HOWEVER, schooled her in it last night and difference in her is phenomenal! So much lighter in the hand, actually wants to work down and round instead of resisting. I call it my magic bit. Sooooo totally recommended.