Craft - allows you to exchange unwanted gear and materials for cool rewards (items, gear)

Divide - Never lose a dime! When you no longer use the gear you can Divide it to retrieve currencies spent on it

Reforge - increase statistics of your gear, very important part of developing your Hero

Smelt- destroy unwanted, low quality gear and get Eternium in the process. A great way to make some space in your inventory when it's full.