FEATURES: • Four plus decade logarithmic scale • Alarm check pushbutton that permits the alarm trip point to be viewed or set from the front panel • Sound volume control and power on light also on front panel • Calibration to within +20% across all decades of instrument • Operates from internal detector or optional external probe • External probe is waterproof to depths of 100 ft. and cable may be up to 300 ft. in length • Readout is small enough to sit on a shelf or may be wall mounted with the included wall mounting brackets • Flashing red light, speaker, and electrical output for alarm indication • Easily accessible calibration pots Available with either Roentgen or SI unit scales