What are the differences between CF (Comfort) and ST (High Strength) series?

CF series (Comfort) is made from modified elastic medical materials. It is convenient for cutting and pressure thermoforming with precise fabrication. This series has balanced the comfort wearing and biomechanical properties.

And ST series (High Strength) is made from thermoplastic polyurethane material with ultra-high hardness. Therefore, this series has a higher stress retention rate, better tear resistance, and better orthodontic effect.