Pure Energy 68/4500
Freak Barrel (Red Back, Red All American Front)
ANS Jackhammer II
Slik Shot Hammer Shaft
New Designz Valve
Even Wal-Mart paint shoots ok in the Freak (but I wouldn't reccomend trying it)
Any size paint
If for some reason you do break paint, you have to run water thru it.
This is one amazing barrel, I've shoot quite a few barrels in my time, and nothing compares to the Freak system. I've shot it on an Impulse, Matrix, 2k2 E-Cocker, Pirahna, and Rebel. It works great on ANY gun. One of the great things about it is, for multiple gun owners like me, is that if you get a new back, you've got a totally new barrel for a differnt gun, Ive got an Impulse, Cocker, and Tippmann back. Compare that to buying boomsticks for each. In the rare occasion that you DO break a ball, it can be a pain to clean sometimes, with mine, im out of the game. Thank god I only break about once every 2 or 3 cases of paint.
I give it 9 out of 10 because of the paint cleaning annoyance.
This is a GREAT barrel for the money. I would reccomend this to anyone, especially multiple gun owners