The Luccarelli Intruder is a fixed transpalatal appliance that utilizes TAD intrusion mechanics to close down anterior open bites. It is the only Intrusion appliance designed with an active second molar spring to significantly intrude the second molars along with the first molars. The Intruder is available with a RPE screw to assist in width development during intrusion if desired.
Please see the below PDF titled "Intruder book" for full description and images.