[20pcs] - Thick Black 8, effective and fast to remove thick cuticles, suitable for with hard skin medium blue 8, suitable for for neutral and hard skin fine white 4, suitable for to daily foot care.[Use with different roughness] - Choose the right roller according to the foot skin condition. You can use a rolling pin. high roughness to quickly remove hard, rough skin, then use a roller to low roughness for fine sanding.[Wide compatibility and packaging] - This product is compatible with Scholl Velvet Smooth, Scholl Velvet Smooth Wet Dry and Scholl Velvet Soft. Note: Not compatible with Scholl Express Pedi.[Good quality, easy to clean. clean] -The cheapest price, the most parts. Our replacement rollers are twice the hardness. micro-diamond crystal abrasive grains, which can withstand wear and remove dead skin more effectively. Washable materials ensure quick and easy cleaning.[Recommended method of use] - It is recommended to clean the sand head after each use, to replace it with new accessories every 10 to 50 minutes. 12 times, not to use more than 2 times per week and to use the same piece for a maximum of 3 seconds. to avoid skin damage.