Flex is soft, flexible, thermoformable, can be heat gun molded, has good clarity, and bonds well to itself. It is an excellent choice for an inner liner material. It can be placed inside of an AFO for added stability, yet still be flexible. Many of our current practitioners use Flex and have had success with it as an inner liner on adult and pediatric AFOs where varying levels of flexion are needed. Another benefit to Flex is that it does not cold form over time. This small addition to your AFO can be held in place with a small piece of self adhesive hook and loop.