You quickly smooth your feet with the Remington CR4000. This callus remover has 2 attachments. Depending on the callus under your feet, choose the coarse roller, or the extra coarse. The roller rotates so that callus disappears in a gentle way without scraping it off. After 1 treatment you see results and your feet are free of calluses. This callus remover works on 2 AA batteries, so you can easily carry it in your toiletry bag. When you are done, clean the top with the supplied brush head.