TWIN I BEAM (TIB) is the 2wd version
TWIN TRACTION BEAM (TTB) is the 4wd version
great axles, if modified, but still have their weak points... if you don't already have it, on a ford.... don't bother with it.... it is a great desert setup, there is a process called cutting and turning the beams, but it is expensive, and seldom done properly..... plus, it is custom parts, which sucks when you break on the trail, and are the only guy running it.... at least with toyotas, all your buddies have the same basic parts, and same general knowledge, etc..... and brought the same parts for spares they can loan you....
