Material: [peeling] Colour: [black-blue] Size: [6.2 cm] Easy to use and installation: callus remover replacement rollers is easy to install and apply, perfectly compatible with foot files and removes calluses. Material: Emery. Replacement rollers contain emery particles with a grain size of 24 to 59 microns, which effortlessly remove dead skin cells. Application: For optimal results, we recommend soaking the feet in warm water before using callus remover replacement rollers to soften the skin. Tips: 1. After each use, remove the callus remover replacement rollers and rinse thoroughly. 2. For optimal results, it is recommended to replace the roll after 10 to 12 applications. Double design: callus remover replacement rollers have a specially developed concave roller that fits tightly to the heel and can be removed quickly and easily.