Small rubber bands used as auxiliaries to an orthodontic appliance to provide a pulling force (traction). They may be used to provide traction within one arch (intra-maxillary elastic) or between the teeth of both jaws ( inter-maxillary elastic). They are usually classified according to their size (⅛ inch to ¾ inch) and the force they are designed to deliver (2oz, 3.5oz, or 4.5oz). The positioning of the elastics determines the definitive tooth movements achieved. They require changing on a daily basis.