| Loss | Mild | Moderate | Severe | Profound |
|---|---|---|---|---|
| Materials | Acrylics, PVCs | Acrylics, PVCs | Hard/Flex Softex, Ultraflex Silicone, Silicone II | Silicone Silicone II Ultraflex |
| Styles | Canal Tip Semi-Canal | Half-Shell Skeleton | Skeleton Full Shell | Full Shell Shell with Helix Lock |
| Canal Length | Regular Short | Regular Long | Long | Long |
| Venting | Large | Medium Small | Small Pressure | Pressure None |