Carbon Fiber Insole for Men & Women 1 Pair: Rigid Shoe Insert for Morton's Toe,Carbon Fiber Insole for Men & Women 1 Pair: Rigid Shoe Insert for Morton's Toe, Match Size: Measure the length of the original insole and select the proper size, the carbon fiber insole must be 1 4 1 2 inch shorter than the original insole. Make sure the hardboard insole is placed under the soft insole for maximum comfort. Carbon fiber insoles are suitable for athletic, hiking, soccer, tennis and basketball shoes, but not for high heels or flip flops.