Durable aluminum oxide sanding cloth is molded into a round cap for callus removing application. This large size covers more area of callus and thick skin on feet. It is also used for sanding nails. The cap is solidly built to be sanitized in an autoclave for resuse. Cap Size: 16mm diamater x 25mm length Mandrel Size: 16mm x 25mm rubber head, 3/32" steel shank.