Die grinders rotate carbide burs, mounted points, cartridge rolls, flap wheels, and other attachments for grinding, deburring, and polishing. They have no guard, so they are not used for cutting. The rated speed of attachments must equal or exceed the grinder's maximum speed to prevent the attachments from breaking or flying apart. Die grinders provide light-to-moderate material removal where an angle grinder would be too large and a rotary tool would be too small. They are used for tasks such as reworking dies, polishing metal, removing gaskets, and smoothing welds. Corded grinders plug into an outlet to allow longer run times than cordless tools in applications where portability isn't a concern. Cordless grinders run on batteries, which makes them more portable than corded tools.