The Model 3 is a portable radiation survey instrument with four linear ranges used in combination with exposure rate, or cpm meter dials.

The instrument features a regulated high-voltage power supply, unimorph speaker with audio ON/OFF capability, fast-slow meter response, meter reset button and six-position switch for selecting battery check or scale multiples of Xo.1,X1,X10 and X100.

Each range multiplier has its own calibration potentiometer.