Sait 90mm Zirconia 7 Hole Velcro-backed Discs for the FESTOOL ROTEX RO 90 and other Random Orbital Sanders with dust extraction holes allowing for a much cleaner job. Available in grits from 40 to 120, zirconium has a high heat resistance that allows it to be put to good use in Timber and metalworking applications . The sharp nature of zirconia grain means it has an excellent cut rate saving time, labour and cost.