Here the pen is pointing to a layer of thin leather (that any shoe repair store has) that has been glued/superglued to the sides and back of the rearfoot post on the orthotic device.
When the patient presented with the squeaky orthotic device, proudly walking for me to prove it, vowing on a stack of Bibles that powder had reduced but not eliminated the squeak. So I carefully put my hand on the orthotic device inside the shoe (yes, this is why I earn the big bucks!! What dangers lurk!?!), and attempted to move the orthotic device to produce the annoying squeak. It seemed to reside loudly in the heel area. Since this type of orthotic device had plastic posts, I covered the posts with leather and made Stacey walk. Wallah, no squeak!! Yes, it is hard to stay humble.