Units of measure — Stored once, in one unit (2)

The unit is a setting on the field's own row, beside its name and type. Untick Accept other units of the same kind and the column takes bare kilograms only. It is a property of the column, not a new field type. That matters more than it sounds: a Quantity type would have to be taught to every write path, every view, every export and every rule about what may be written where. A unit on a Number field inherits all of that for free, which is why a quantity column filters, groups, sorts, charts and exports exactly like the plain number it still is.