just read the post that only the lite is avail. FT has more than one type of KFL?
I'll try to keep this simple ... the only difference since they both have air flow control, the full 3.1 is taller and has a reservoir at the bottom to catch extra juice from overwicking, to help prevent flooding. Also the Lite / R91 clone fills through the bottom with a Philips head, where as the 3.1 has to be filled with a special plastic needle tip that are hard to come by. (usually have to order 50 of them, I just top fill it... I've also heard of people having problems with the fill port on the full size, there's a little ball in there that can get stuck, or leak)