400ex - 450r carriers ?

[400exshop]

Need some help. Can some one tell me what the different's is in a 400ex carrier and a 450r ? Or way thay will not inter-change ?
is one wider ? is one thicker ? just what is it that is different from the to ? H E P L ! ! ! ! ! ! ANY ONE ? ? ? ? ? ? ? ?

[Sweaney]

Spell check??????????

[400exshop]

my bad is this better ????????

[dustin_j]

The 400ex carrier is wider than the 450r carrier.