Which of the following statements is true about the force applied to the maxilla to restrict A-P growth?
1) It allows 'catch up' growth of the mandible
2) It can direct force to intrude or extrude molars to control vertical dimension
3) It has to be worn for 14 hrs with a force of 500g per side
4) It is applied to the maxilla because the mandible grows later than the maxilla