Extra coarse grinding heads with diamond crystals. Effectively removes very hard skin and gives soft feet. Soft beautiful feet without effort. Visible results after one use. Fits all Scholls foot files. Wet and dry grinding headsUse:We recommend that you only use Scholl's sanding heads with Scholl Velvet Smooth electronic foot files and replace them every 3 months for optimal effect. You can remove dry skin with this sanding head on wet, damp or dry feet. For use in/under water, use only with Scholl Velvet Smooth Rechargeable Waterproof Foot File. Save the outer packaging for future reference. See the packaging of your Scholl Velvet Smooth electronic foot file for full instructions for use. Replace the sanding head when you notice that it is becoming less efficient. Follow the steps below to ensure foot file is turned off. Use only Scholl Velvet Smooth sanding heads with this foot file Scholl Electronic Foot File Refill Extra Coarse