Also called a radial blower, squirrel cage, or squirrel wheel compressor, a centrifugal compressor consists of an axle to which is mounted a cylindrical assembly of compressor blades. The compressor operates by using the centrifugal force applied to an air mass to achieve compression. Centrifugal compressors are used throughout industry because they have few moving parts, are very energy efficient, and give higher airflow than a similarly sized reciprocal compressor. Their primary drawback is that they cannot achieve the high compression ratio of reciprocal compressors without multiple stages. Centrifugal compressors however are more suited to continuous duty applications such as ventilation fans, air movers, cooling units, and other uses that require high volume but fairly low pressures. While technically centrifugal blowers can operate in reverse, due to blade design and other factors their efficiency is greatly reduced. Centrifugal blowers are used in some small jet turbine engines.