Which of the following appliances is not used for slow maxillary expansion?

Hyrax appliance  This type of expander uses the Hyrax (hygienic rapid expansion) screw. It has heavy wires that are adapted, welded and soldered to the palatal aspects of the bands in the permanent molars. It is used for Rapid palatal expansion. Examples of slow expansion:  Jack screw Coffin spring Quad helix appliance Textbook of ORTHODONTICS Sridhar Premkumar