The Multi-P® Sizer to use with Multi-P® which guides erupting teeth with the help of the patient’s own muscle forces to an ideal position in the dental arches. A good occlusion is established and development of severe malocclusions avoided. The appliance has a high and low model. The high model, designed for the treatment of open bite cases, has a thickened molar region. Measurements are from left side to right side between lateral and cuspid.