I recently started a job that requires me to be on my feet for 8 -10 hours a day on a concrete floor. At 49 my feet were killing me especially the balls of my feet.I tried everything I could buy at stores but could not find anything that would help much, untill I tried these Spenco's.Wow, what a difference. These things are a godsend. They are well built, they stay in my Red Wing boots without moving and you can tell they will last a long time. I no longer have the ball of foot pain that I had, now its just my back pain I have to deal with :).I am getting a second pair for my tennis shoes for the long walks in the mall. They fit im my boots and tennis shoes.I wear a size 9 mens, and got the medium insert, its the right size for me.