I went to a foot specialist and she recommended custom orthotics, though she wanted me to go to a specialty shop. I went to the machine at Walmart and the testing sent me to the 440 Dr Scholls. I bought them and almost immediately after use my back pain improved. Now I can walk for several hours with no problems. They last about 6 to 12 months of continuous wear. When the pain starts coming back I know it's time for a new pair.