One of my legs has become shorter. It is either no cartridge in my hip or knee replacement on other leg was made too large. Rather than explore that with possible surgery these heel lifts are perfect. My doc sent me to a specialist for heel lifts. Made too big. Physical therapist made a lift, too big. These are perfect. Very easy to adjust. I even had someone comment while I was walking the dog asking what happened, I'm not limping. These are really great.