The W-Arch, also known as the Porter appliance, is crafted from .036 wire. Activated by opening the apices, it offers adjustable anterior or posterior expansion. For optimal forces, manually open it 3-4 mm before insertion. Expansion should proceed at 2mm per month until the crossbite is fully corrected.


  • Bands on the 1st permanent molars
  • W Arch wire

Suggested Materials:

  • Wire: .036 Chromium Cobalt wire or Stainless-Steel
  • .040 Chromium Cobalt tube
  • Silver Solder (Cadmium Free)