Inventory - Item Level Sort

Zalaan

I have seen a couple of photos of people's inventory screen while searching forums and they have a heading "Level" to the right of "Name". I assume that this is an option for sorting items by level, particularly armour, weapons, etc. Can anyone tell me what addon, or in-game option will permit me to do this? I would really like to be able to sort my gear by level - particularly my bank.

Thank you