The best-known removable retainer for teeth straightening is the Hawley retainer, which consists of a metal wire that typically surrounds the six anterior teeth and keeps them in place. It is anchored in an acrylic base plate that sits in the palate (roof of the mouth). The advantage of this type of retainer is that the metal wires can be adjusted to finish treatment and continue minor movement of the anterior teeth as needed. Recently, a more aesthetic version of the Hawley retainer has been developed. For this alternative, the front metal wire is replaced with a clear wire called the ASTICS. This is intended to be adjustable similarly to the traditional Hawley retainer, which is not practical with vacuum-formed. The original clear bow named QCM, was developed to eliminate the look of wire across the facial surface of the arch. Excessive breakage has made this impractical for younger patients.