Value Assignment Attribute for Characteristics 
In characteristics maintenance functions, you define whether a characteristic is:
If a characteristic is a single-value characteristic, the characteristic can only have one value.
For example, you can only select one model for a car.If you allow multiple values for a characteristic, the characteristic can have more than one value at a time.
For example, you can select several different values for characteristic EXTRAS of a car.A restrictable characteristic is in effect a single-value characteristic.
However, the allowed values for a restrictable characteristic can be restricted dynamically during the configuration process. For example, if the allowed values of a characteristic are restricted by dependencies to certain values, these values can be temporarily assigned to the characteristic during the configuration process, but the configuration is not complete until you select one specific value. 
The value assignment attribute of a characteristic is a global attribute that applies to the characteristic wherever it is used.
Most characteristics used in dependencies are single-value.
Check the settings in Customizing for the Classification System. By choosing Characteristics® Define default Settings, you can enter default values. Please ensure that the Multiple values indicator is not selected, because this would mean that the characteristics you create have Multiple values allowed as a default setting.Multiple-value characteristics and restrictable characteristics are difficult to process in object dependencies and should be used with caution.
For information on how multiple-value characteristics and restrictable characteristics are processed, refer to: