Energy Range: 60 keV - 1.3 MeV. The gas detection device has a built-in counter tube and a connector for an connecting an external probe. When connecting an external probe the internal probe is turnd off. The external probe is automatically recognized: (eg "ext 17" means desonde 6150AD - 17 is connected.) The measurement range and unit adjust automatically. Data to a PC can be sent by one pin of the connector. When connecting a probe the cable length can max be 100 meters. Standard sizes are 1.25 m, 3 m, 10 m, 20 m, 75 m and 100 m. Features in numbers Analog display range: 0.1 ASV/h - 10 mSv/h. Digital display range: 0.1 ASV/h- 9.99 mSv/h. Measurement range can be calibrated: 0.5 ASV/h - 9.99 mSv / h. Energy Range: 60 keV - 1.3 MeV.