A filter cartridge for use in a filter system, in which the cartridge has no structural metal parts and is adapted for environmentally acceptable disposal. The housing includes a brush receptacle and the toilet brush includes a handle and a cleaning head having a plurality of bristles. The breathable moisture barrier of the present invention provides a sufficiently high MVTR to allow rapid humidity equilibration within the sensor mat so as to better track rapid changes in the passenger compartment environmental conditions upon starting the car and applying either air conditioning or heating. The support block includes a set of support passages in which the distal ends of the guide pins are cemented, and a support face which is at right angles to the set of support passages. The present invention can be carried out by: administering a preparation comprising as an active ingredient a pyrimidine compound or its metabolite which acts as a substrate for a pyrimidine metabolizing enzyme, in which compound or metabolite at least one of C, O and N is labeled with an isotope; and assessing in vivo pyrimidine metabolizing activity based on the amount of excreted metabolite. The system includes a card writer for writing configuration data from an application service provider to the card, and a card reader for downloading the configuration settings into the network access equipment from the card.