It's adhesive, off protective layer, and paste on the device , will not fly off when working. Effective to remove dead skin, dry skin, calluses and corns. (before using machine, please soak off foot with water, to soften feet skin.) One Person One Disc,More Sanitary and Healthy,Suitable For Nail & Family Easy To Paste On The Electric Foot File,After Using, Easy To Remove It From The Electric Callus Remover. Please note: this is replacement sandpaper disk, not include electronic foot file !!! The sandpaper discs is used for electric foot callus remover machine. Colour: Black Material: + Emery Size: diameter 4.3cm Package Contents: 1 Box * Replacement Sandpaper Disk (60pcs) (Coarse 100 Grit) Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.