| 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  |