The Combination Tester CMB-S or Combi Compact is one of the most compact portable combitesters available. The instrument is designed especially for installers or maintenance people who frequently need to check or inspect LV-installations after modification, initial inspection or addition. The tester can inspect, measure and test different kinds of RCD’s (normal and selective), net or loop impedance and (insulation) resistance on LV-installations, according the EN 61557 regulation. Voltage and frequency can also be measured by the CMB-S.