You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Which of the following appliances is not used for slow maxillary expansion? and explain in detail?
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