A Rotary screw air compressor is a compressor type of gas, such as an air compressor, which uses a positive displacement mechanism of the rotary type. They are commonly used to replace the piston, where large high pressure air volumes are required, either for industrial applications such as chillers, or use high-power air tools such as pneumatic drills and impact wrenches. For smaller sizes of rotor leakage inherent to the rotors becomes much larger, leading to this type of mechanism not suitable for small compressors of air.