The usual Hawley retainer is constructed with a 3×3 labial bow and a set of adams clasps. It is easily adjustable with the labial omega loops and provides excellent retention with the clasping placed between the premolar and molar.
Hawley retainer with expansion screw
A retainer with an expansion screw is used to broaden the dental arch in a transverse, mesial, and/or distal direction. Smaller screws may be used to align individual teeth. In most expansion screws, a single activation is equivalent to .225mm of opening. A single activation is usually recommended every 5-7 days