The compressors can be used as a pressure or vacuum pump for conveying air and non-explosive gases as well as gas-air mixtures. The compressors are air-cooled, meaning they are 100% oil-free. The aluminium fan wheel rotates inside a die-cast casing with a side-channel. Air is sucked in, and propelled by the fan wheel and side channel on a spiral course, accelerating several times, until it reaches high pressure and exits through the pressure channel. The compressors work in any axial direction and are designed for long-term operation.