This fact is from Functional Appliances in Orthodontics. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
Twin Block = most popular functional appliance
Activator = Andresen = most studied
Frankel = vestibular shield = functional regulator
Bionator = modified activator by Balters
Herbst = fixed functional appliance
All work by mandibular advancement in Class II.