All models feature internal GM (Geiger-Mueller) detector for greater handling ease, anti-saturation circuitry, and red count light.

• Audible beeper can be switched on or off
• Built-in battery check, long battery life
• Carrying case is included

Monitor 4—Meter detects alpha, beta, gamma, and x-rays utilizing an uncompensated halogen-quenched GM tube with a 1.5–2.0mg/cm2 mica end window

Monitor 4EC—The Monitor 4EC is the Monitor 4 with an energy compensated GM detector.

Typical efficiencies using 2[pi] geometry are:

Smallest detectable level of 125I is approx. 0.02µCi. Recommended detection levels for 125I is 0.5mCi and up. Gamma sensitivity is 25cps/mR/hr.

Analog meter reads 0–0.5, 0–5, 0–50mR/hr. or 0–50,000cpm, in three settable ranges. Audible beeper can be turned off.

cpm: 22,000 [source Sr-90 (0.0201 µCi)], 14,000 [source Tc-99 (0.043 µCi)], 17,000 [source C-14 (0.130 µCi)]