Use these insoles in your shoes for extra padding or in combination with your current insoles. By placing them underneath your shoe's insoles or custom orthotics, you can create a snug fit that is great for those with narrow or low volume feet. The top layer is a durable, odor-resistant black polyester nylon and the cushion layer is 4mm of high density shock absorbing foam. Men's shoe sizes - Small(5-6.5), Medium(7-8.5), Large(9-10.5), X-Large(11-12), XX-Large(13-14) Women's shoe sizes- Small(6-7.5), Medium(8-9.5), Large(10-11)