The Medium Opening Activator (MOA), fabricated here in clear heat cure material.

Design includes: - 

 *   Lower incisal capping 3 / 3 .
 *  Anterior Palatal wire 3 / 3 in 1.0mm S.S wire.
 *  Labial Bow 3 / 3 - 0.9mm S.S wire.
  *  Adams clasps 64 / 46 - 0.7 mm S.S wire.
  *  Occlusal rests 64 / 46 - 0.8 mm S.S wire.
  *  Acrylic connecting 'struts' / vertical supports.

Another series of MOA pictures.

Design includes (as above) plus: -

v Double Adams clasps 65/56 - 0.7mm S.S wire.
v Preformed occlusal rests 65/56 - 0.8mm S.S wire.

Medium Opening Activator with upper model removed.

Medium Opening Activator with lower removed.

Medium Opening Activator with lower removed.

Medium Opening Activator with lower removed.

Medium Opening Activator with upper model removed.

Medium Opening Activator with upper model removed.

Medium Opening Activator with upper and lower models in situ.

Further reading: - Functional Appliances in Orthodontic Treatment (an atlas of clinical and laboratory construction) - Harry. S. Orton.  ISBN - 1-85097-012-2.