It's adhesive, off retaining layer, and paste on the gadget well, won't fly off when working. Effective to take away , dry skin, calluses and corns. ( using machine, please soak off foot with water, to melt feet skin.) One Person One Disc,More Sanitary and Healthy,Suitable For Nail & Family Use Easy To Paste Well On The Electric Foot File,After Using, Easy To Remove It From The Electric Callus Remover. Please note: this is replacement sandpaper disk, now not consist of electronic foot dossier !!! The sandpaper discs is used for electrical foot callus remover machine. Colour: Black Material: EVA + Emery Size: diameter 4 Package Contents: 1 Box * Replacement Sandpaper Disk (60pcs) (Coarse 80 Grit) Only the above kit content, other item will not be included. Note: Light and diverse displays can cause the color of the article in the photograph barely diversified from the real thing. The measurement allowed error is +/- 1-3cm.