GCA-06 Professional Geiger Counter - Nuclear Radiation Detection Monitor with Digital Meter and Internal GM Tube - NRC Certification Ready- 0.001 mR/hr Resolution -- 1000 mR/hr Range NRC CERTIFICATION READY - NRC certification can only be given by U.S. Government licensed laboratory. The NRC certificate certifies that the radiation reading from the Geiger counter is accurate. COUNTING RESOLUTION AND RANGE: 1 Count Per Minute (CPM) - 10000 Counts Per Second (CPS) DETECTOR SENSITIVITY: Detects Alpha particles above 3 MeV in energy. GM tube has a thin mica window that allows alpha radiation to be detected. Beta radiation above 50 KeV; X-Ray and Gamma radiation above 7 KeV RADIATION RESOLUTION AND RANGE: 0.001 mR/hr resolution / 1000 mR/hr Range (Imperial measurements); 0.01 uSv/hr resolution - 10 mSv/hr range (Metric) NIST TRACEABLE CALIBRATION - Factory calibration using an NIST traceable radiation source to insure accurate radiation measurements.