Provide vertical titration/simulation for any device that opens in the anterior such as the Herbst, Somnomed, or Suad design. The nine "keys" range from 3mm to 11mm in 1mm increments and fit between the upper and lower units of the device being tested. They are held in place between the device components when the patient applies a modest closing pressure much like the MPS are secured between the teeth for different vertical positions. A-P (H) adjustments are per mfg. instructions for device being tested. NOTE: Any anterior space between the upper and lower device units must be subtracted from the VTK width to obtain the net anatomical vertical increase.