NYALOX 3 Pack Cup Brushes Are Conveniently color coded with Blue for Fine 240 Grit, Orange for Medium 120 Grit and Gray for Coarse 80 Grit. Far superior to wire brushes and lasts up to 10X longer. Will not rust and bristles will not shed or puncture skin. Maintains shape for the life of the brush. For use on metals and wood to sand and clean unfinished and rough woods also cleans tiles and stones and will not gouge.