Magnet systems of the BKM-HD/VI type have been developed especially for use in pneumatic-transport systems operated at an overpressure. The standard unit is available in two dimensions, i.e. a housing 150mm square and a housing 200mm square. The system is supplied with a separate receiving tray which must be slid onto thhe opening at the base of the housing when cleaning the unit. This opening is hermetically sealed during the production process.