Air-powered 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 for cutting. An attachment's rated speed must equal or exceed the grinder's maximum speed to prevent the attachment 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. These tools run on compressed air and are typically lighter than corded or cordless grinders to help reduce operator fatigue during extended use. They contain few moving parts, so they tend to run cool and have a long lifespan.