The Herbst Appliance is a mandibular repositioner that has been in use for many years in orthodontic and TMJ therapy prior to its modification for treatment of sleep disordered breathing. Using a telescopic sliding tube connection between the upper and lower retainer portions, the Herbst permits lateral and vertical movement while maintaining the desired mandible-forward position. It is sturdy and fully adjustable to find the most effective and comfortable position. Adjustment of position is quick, easy and very accurate. Base materials available include thermoactive and soft materials as well as hard acrylic, with retention by friction grip and optional clasps.