* active settings "Allow using different units of measure" in Settings > Configuration > Sales >  Quotations and Sales Orders >  Product Features


* During the creation of a category, tick the box 'To weigh'.

.. image:: ../static/description/uom_categ_change_toweigh.png
   :alt: Change the field 'To weigh' for every category
   :width: 400

* You can set every product existing with the new 'To weigh' parameter

.. image:: ../static/description/uom_categ_button_toweigh.png
   :alt: Set 'to weigh' in each product of this category
   :width: 900