The 3D® Quad-Helix Appliance is a multi-purpose maxillary arch development appliance. It plugs into the 3D Lingual Tube and the twin posts to produce a tight friction-lock (with no free play). The .036 Tru-Chrome™ (RMO) stainless steel construction assures both stability and flexibility. In addition to being used for traditional lateral arch development, this appliance can be used for unilateral expansion, molar rotation, molar buccal or lingual tip, molar buccal or lingual torquing, as well as anterior advancement.