It's adhesive, peel off protective layer, and paste on the device well, not fly off when working. If your electric callus remover tool can be applied this replacement sandpaper disk, you can buy it. One Person One Disc, More Sanitary and Healthy, Suitable For Nail Salon & Family Use, Effective to dead skin, dry skin, hard skin and callouses. (before using machine, please soak off dead skin, to soften feet skin.) Self-adhesive Design, Not Fly Off When Working. Easy To Paste Well On The Electric Foot File, After Using, Easy To 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: sandpaper size:4.3cm Package Contents: 3 x Box (180pcs) Replacement Sandpaper Disk Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.