You can filter feature classes based on a single property, multiple properties, a location in the model that you specify, or a set of conditions.
You can filter data before you add it to the model. In that case, only data that matches the filter criteria is added. You can also create subsets, using a filter, after you add data to the model.
You can select data using a filter. If you specify the filter using the Edit menu, you filter all data in the model, but you can use only the properties that all feature classes have in common. If you select features for a feature class or subset using a filter, you can specify the properties available for that feature class or subset.
The result of a filter expression must be a Boolean value.