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. Depending on the type of hammer and the bits used, air hammers can chisel, cut, chip, scrape, shape, split, and drive. 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.