Angle grinders can remove surface material by rotating grinding wheels or cut through material by rotating cut-off wheels. Because their heads are positioned at a right angle to the tool body, they are more compact than vertical grinders and provide better view of the wheel and work area. Grinders with side handles enable for a two-handed hold, which improves control and stability. Angle grinders are often used to polish concrete, stone, and metal, grind welds, prepare metal and concrete surfaces, bevel cutting tools and material edges, cut metal plates and pipe, and grind welds. In settings where portability isn't an issue, corded grinders plug into an outlet to provide longer operating periods than cordless instruments. Cordless grinders are more portable than corded grinders since they run on batteries.