The Ryobi Tools 18V ONE+ Angle Grinder, No. P421, delivers 6,500 RPM and features a 4 1/2" grinding wheel, on-board wrench storage and a GripZone overmold combined with a three-position side handle. The grinder is sold as a bare tool, and works with any 18V ONE+ battery. An upgrade to lithium-ion or LITHIUM+ batteries is an option for lighter weight and better performance, according to the company.