The concept of the product is good, the material the product is made out of is terrible. If the insole itself (not the small part of metal which is located under the ball of the foot) was made out of a better material, this would be a great product. The insole keeps sliding up the heel of my shoe, causing me to stop walking and fix it every ~10 mins. I am recovering from surgery post a grade 3 turf toe incident in which i severed some sesamoid ligaments in my big toe joint so I am very tender. I am 16 weeks post op and would not be able to wear these with any runner/shoe. The only way these help is in a thick soled shoe (Hoka One One).