Cordless cut-off machines rotate continuous-rim abrasive blades to make straight or angled cuts in metal alloys and other hard materials that can't be cut with toothed blades. Also known as abrasive cut-off saws, they grind their blade through material and leave rough, burred edges. They run at higher speeds than chop saws but cause more heat buildup in workpieces. The blade produces sparks during cutting, so cut-off machines are not for use in areas with flammable materials. These cordless machines operate in areas without access to wired power, eliminate the tripping hazard of a cord, and run on brand-specific batteries.