I have now bought several nice shirts from Ebayers only to see that they were 3XL when I was looking for (and they posted) that the size was 3XLT.  For everyones information the cut on a 3XLT is (or is supposed to be) longer and therefore on a tall person  a 3XL may fit around the torso but may not have enough tail to tuck in.  Now having said that there are some 3XL's especially in T's and Polo's that might have a long enough tail. Probably a good idea to be clearer is to provide the length from the collar to the bottom of the tail. Also, it is confusing, IMHO, to put "XXXL , 3XLT , 3XL, XXXLT" or combinations thereof in the title -- I generally skip over those because I feel the lister really does not know the difference--- or cares.