Assigning the speed of your NIC for wan and lan

[Jesse7]

Quick question.  When assigning the speed for my Wan and LAN which are 10 Megabit and 100 Megabit.

I type in 10 and select Megabit/s.  Click save and apply if it asks too.

There are also other options.  The top/default option is Mb.  Which I assume is Megabit as well? So the same option is there twice? is there a difference?  Anyway,  if I select Megabit/s and save it still selects Mb.

Seems wierd.