This intrinsically safe general purpose ratemeter is patterned after Ludlum's best selling Model 3.   It was designed and tested to USA standards for instrinsic safety, permitting it to be used in potentially explosive atmospheres.  The Model 3-IS can only be used with select detectors to sustain the intrinsic safety rating.  The optional detectors for this application are:

Like the Model 3 before it, the 3-IS retains the well-deserved reputation for accuracy and long-lasting dependability. The aluminum cast instrument housing, with its separate battery compartment and accompanying metal handle, offer an industrial robustness and quality that promote long-lasting protection and instrument life. The front-panel controls include a rotary switch for selecting the four-decade range, instrument shut-off, and battery test, an audio on/off switch, a fast/slow response switch, and a count reset button. The analog meter comes in a variety of measurement ranges and units to support the external radiation detector selected.

A one meter (39 in.) straight type detector cable equipped with special connectors designed to prevent quick or accidental disconnection in the field is included in the price of the instrument.