Available with Data Interoperability license.
Spatial ETL tools are user-created geoprocessing tools that can transform data between different data models and different file formats. You create them with FME Workbench in a translation workspace and save them in a toolbox.
Initiating creation of a new spatial ETL tool opens the Create Translation Workspace Wizard. The wizard prompts you for information about the data source and data destination, then starts FME Workbench with a diagram of your dataflow. You can customize the default dataflow by adding or deleting connectors, inserting transformers, and editing parameters.
Usage
Spatial ETL tools are capable of a wide range of processes and dataflows from simple format translations to complex transformations that restructure geometry and attributes. They can be used as stand-alone geoprocessing tools, published in toolboxes as geoprocessing services 
using ArcGIS for Server, or exported as custom formats and utilized in the FME reader gallery.
Possible uses include the following examples:
- Filtering attributes and merging them with other feature classes
- Using attribute values to create unique feature classes on the fly
- Separating data using test criteria
- Creating line features from coordinate values