Concrete chain saws make straight and plunge cuts in hard, abrasive materials such as masonry, cured concrete, and rock. They use a diamond-grit embedded chain that rotates around an oblong bar to abrade the workpiece. The bar allows for deeper cuts than handheld concrete saws. Water is used to lubricate the cut, which keeps the chain cool and reduces airborne contaminants. Gas-powered concrete chain saws are powered by fuel to provide sustained power for long periods of time. They produce more power than air-powered saws.