PRECISION DUPLEX DRESSER is designed to simultaneously dress both sides of a grinding wheel, precisely and without deformation. It is useful for the thining of grinding wheels or the dressing of thin wheels. manufactured of tool steel and hardened throughout to HRC 60 for life time use. SPECIFICATIONS: Maxi width of wheel......40mm(1-9/16") Maxi dressing depth......40mm(1-9/16") Mini dressing width.....0.2mm(0.0079") Graduation......0.02mm(0.0001")