Aluminium oxide-mounted stone set for grinding metal and hard plastic. Includes 22mm ball, 25mm cylinder, 24mm conical, 19mm taper and 13mm taper stones. 6mm arbor. Max 2800rpm. Aluminium oxide-mounted stone set for grinding metal and hard plastic. Includes 22mm ball, 25mm cylinder, 24mm conical, 19mm taper and 13mm taper stones. 6mm arbor. Max 2800rpm.