The input feature class or layer containing features to iterate.
Group By Fields
The input field or fields used to group the features for selection. Any number of input fields can be defined, resulting in a selection based on a unique combination of the fields. If a field is not specified, the Object ID is used to iterate over features.
Skip Null Values
Specifies whether null values in the grouping field or fields are skipped during selection.
A feature layer that can be used in other geoprocessing tools that accept a feature layer in ModelBuilder.
The field values returned by each iteration. If more than one group by field is chosen, the values are concatenated <field value1>_<field value2>.