MC. MILLER 400A Analog Resistance Meter

The current source in the MILLER-400A, which supplies current between the C1 and C2 terminals (with a load applied), is a 12V(rms) crystalcontrolled 97Hz square wave oscillator and the voltmeter inside the unit which senses the potential difference (voltage drop) appearing across the P1 and P2 terminals, employs a very narrow band-pass filter centered at 97Hz What this means is that resistance measurements taken by the MILLER400A are unaffected by any stray interference signals (having frequencies other than 97Hz) that may be present in the earth during a measurement.

The MILLER-400A has a resistance measurement range from 0.01Ohm (0.01Ω) to 1.1 MOhm (1.1MΩ) that is achieved by means of a set of 8 range settings and a system of internal “standard” resistors. External resistances (resistance values under test) are compared against the internal “standards, via a null balancing system, resulting in a determination of the external resistance values. 

Features
Rugged, lightweight case - safe to use on wet ground
Weather resistant, even with lid removed
Convenient case lid removal for ease of movement, with test leads attached, to new measurement locations
Resistance measurement range from 0.01Ω to 1.1 MΩ
Resistance measurements are unaffected by any stray interference signals that may be present in the earth during readings, due to the use of narrow band-pass filters centered at 97 Hz (the unit's operating frequency)
Runs on a set of C-Cell Industrial Alkaline Batteries. No need to periodically recharge the unit or to plug it into a power source

Specification
Storage temperature range (with batteries installed): -30°C to 50°C (-22°F to 122°F)
Operating temperature range: -20°C to 54°C (-4°F to 129°F)
Accuracy: ±5% of reading
Weight: 7.0 lbs (3.175 kg)
Width: 12.0 inches (30.5 cm)
Length: 10.0 inches (25 cm)
Height: 5.0 inches (12.5 cm)