what is this
 

one simple question what is this http://www.rc-monster.com/proddetail...=6vubec&cat=21 and what dose it do and will i need to run on two 6 cell packs with the 9920 and can someone plz show me pics of how this controler is setup on their truck thx

The link didn't work, but what I could tell from the text in the link, it looks like it is the UBEC? http://www.rc-monster.com/proddetail...=6vubec&cat=21

It allows you to hook up as many cells (up to 40v IIRC) and outputs a clean 6v dc for your receiver and servos. It is a switching unit which means it is efficient and dissipates little heat. The BEC in most controllers is NOT digital, but simply a linear regulator. This means it is much less efficient (although much less complex) and heats up a lot more, more so with more cells. That's why there is a limit on the number of cells you can use. The idea is that you disable the BEC in the controller and use one of these. You'll have more power for your servos and won't unnecessarily heat up the controller.