List Weight Classes
System > Localization > Weight Classes
Units of measure to use in product options and shipping by product weight OR add new weights, for example, if you sell your products using ounces. Kilogram is the default.
Set the DEFAULT in System > Settings > Details Tab.
To add a new Weight class click the button
What ever you have set to 1.00000 is your base weight class. Any other weights in there need to be a factor of your base class.