Proven in industry water management plants and also on construction sites. The units are notable for their high performance (even at low temperatures), low weight, simple control and quiet operation. The practical carrying handle enables the units to be easily carried by one person whilst still remaining capable of being stacked. The units incorporate an energy-saving rotating piston compressor, a large water tank with automatic cut-off when full, an integral hygrostat, an air filter and an operating hours counter. A load counter is an optional extra.