All Prokinetics® Natural Body Balance™ Replacement Insoles employ the same technology and provide the same corrective benefits. The replacement insoles are specifically intended for use in footwear that includes original removable insoles. The ProKinetics® Natural Body Balance™ Insoles contain customizable components. The red corrective wedge is pre-installed and provide 3 mm correction. The kit contains an additional 3 mm orange wedge that may be attached over the red wedge to together, provide 6 mm correction. The replacement insoles also include removable arch supports that must be attached permanently with the included adhesive if desired. Most people can safely remove them and rely on the forefoot correction. The heel includes a slight amount of cushioning (blue) and is cupped. The top material is moisture wicking and made of faux suede fabric. The body and insoles and the parts are made of EVA (the same material as most sneakers). With normal wear and tear, you should expect 12-18 months durability. Follow the trim lines on the toe portion to size for your shoes.