In certain embodiments, an apparatus for treating a breathing condition includes a body, a threaded member, a hook, and a receiver. The body comprises a front stop, a rear stop, and a guide extending between the stops. The threaded member couples between the stops and rotates relative to the body. The hook couples to the guide, comprises a threaded passage and an arm that engages a lower arch, and travels in a forward direction along the guide to adjust the position of the lower arch. The receiver couples to the lower arch and comprises a shelf that engages the arm of the hook. The apparatus may include an extender coupled to the receiver and providing a shelf that is more rearward than the shelf of the receiver. The apparatus may include a post that couples the apparatus to another device. In certain embodiments, a removable receiver, which may be one of a plurality of removable receivers with different dimensions, is removably positioned within a recess in a posterior surface of a lower arch and is engaged by a connector of an upper arch to define the relative positions of the arches.