The dual-channel counter CSS-Fluid is accommodated in a splash water protected diecasting shell. The liquid feed is executed with the help of an standpipe or the pressure control valve. Alternatively, a liquid pump may be used in depressured systems. All parameters (measuring time, particle size and threshold values) can be parametered with the help of the PC. The particle number can be transferred via the current interface 4-20 mA to an evaluation unit. The overstepping of the threshold values can be queried at two potentialfree contacts at the box.