you're going to have to be more specific. Have you even owned a paintball marker before?
I've never heard of a "fusion box" before and i've got no idea what this black tube is that you're talking about either.
Teh fustion looks like a staked tube marker similar to an ego or timmy. is that correct?
ere's a manual for them
http://www.dangerouspower.com/orig/downloads.php, I highly suggest hat you read them.