Air-powered hammers strike chisels and punches against surfaces for aggressive material removal and demolition work. They have a longer stroke to deliver more powerful percussive action than scalers. Chisels and punches can be changed out for different blade and tip styles as long as the bit shank is compatible with the hammer. They are held in the barrel of the hammer by a retainer, which keep the bits from flying off the tool during use. Depending on the type of hammer and the bits used, air hammers can chisel, cut, chip, scrape, shape, split, and drive. Air hammers perform general material removal and light chipping. Chipping hammers perform heavy material removal and light demolition. Rivet-busting hammers remove or set rivets, cut through tanks, and break up brick or concrete. Riveting hammers set rivets for assembling parts and repairing metal structures.