Are you sure they’re the same? They look almost identical, and the only way to tell for sure is to compare the gears to each other directly, just like in my photos – the difference in diameter is just too small to see unless comparing side by side. I’m afraid I don’t have the part numbers any more as I threw their packaging away (one of them came in a Britpart box for a different component anyway – it had been stored in its sealed plastic bag loose and the box had been used for potage). If the output shaft gear is black, as my new one was, then that is a good indication. Of course, it’s not impossible that you already have a SII SuffB box anyway – there’s no way to tell unless you know the serial numbers or count the teeth on those gears as they are otherwise identical to the last of the SIII 4cyl transfer boxes, or someone may have made the same mod (knowingly or accidentally) on a previous rebuild of the unit…

Try removing the intermediate gear cluster to compare the spur gear diameter to the new one – it’s not a difficult job to get that out and refit it if the new parts are incorrect. Dunsfold Land Rover supplied one of my gears and Craddocks the other, so they can both provide part numbers if you still need them.