Intrinsically Safe Gamma Survey Meter - Model 3-IS-1
Introduction

This intrinsically safe general purpose ratemeter is patterned after Ludlum's best-selling Model 3. It was designed and tested to USA standards for intrinsic safety, permitting it to be used in potentially explosive atmospheres.
 
This instrument includes an internally housed, energy compensated GM detector with a gamma detection range of 0.1 mR/hr to 1.0 R/hr. The Model 3 type instruments are well known for their 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.