The World's Greatest Insole features Impact Gel in the soles and heels for improved comfort and impact resistance. Impact Gel's insoles are designed for full comfort for the ball and heel of the foot. Ideally designed for men's and women's athletic shoes as well as work boots, and men's casual shoes where there is ample space to replace the original manufacturer's insole with Impact Gel Insole. Remove the manufacturer's insole and replace it with the Impact Gel Insole for best results. These insoles can be trimmed to fit the exact shape of your shoe.