- The A2 focuses on arch development and continuing habit correction. - The breathing holes are removed to establish and maintain continuous nasal breathing while the myofunctional features remain present in the appliance to promote correct habits. - The firmer polyurethane material puts more force on the anterior teeth to improve their alignment, while promoting arch development at the same time. - Move to the A3 when the A2 has corrected the arch form, breathing and myofunctional habits. **For further product information, please contact Chat Support**