Used working Ludlum model 3 survey meter /geiger counter  -professional survey meter with 44-9 probe (for alpha, betta and gamma radiation detection. New Battery included. Last calibrated 2014.  If not satisfied, You can return this unit withing 5 days for a full refund minus shipping

The Ludlum Model 3 Survey Meter is the industry standard of radiation survey meters.  The meter has a rugged design and microprocessor electronics. With proper care, the Ludlum Model 3 will last decades. It operates on two "D" cells for approximately 200 hours. The Ludlum Model 3 has adjustable high voltage to 1500 volts and includes external calibration controls. The four counting ranges are x0.1, x1, x10, x100. Typical Counting Range is from 0 - 200 mR/hr, or 0 - 500,000 cpm. The Ludlum Model 3 is supplied as shown with built-in speaker, strain relief cable, probe clip-on handle, two "D" cell batteries

We opened to inspect internally and the unit is clean inside and out.

INDICATED USE: General purpose survey
COMPATIBLE DETECTORS: G-M, scintillation
METER DIAL: 0 - 2 mR/hr, or 0 - 5k cpm, BAT TEST (others available)
MULTIPLIERS: X0.1, X1, X10,X100
LINEARITY: Reading within ±10% of true value with detector connected
CONNECTOR: Series "C" (others available)
AUDIO: Built in unimorph speaker with ON/OFF switch (greater than 60 dB at 2 feet)
CALIBRATION CONTROLS: Accessible from front of instrument (protective cover provided)
HIGH VOLTAGE: Adjustable from 200 - 1500 volts
THRESHOLD: 30 mV ± 10 mV
RESPONSE: Toggle switch for FAST (4 seconds) or SLOW (22 seconds) from 10% to 90% of final reading RESET: Push-button to zero meter
POWER: 2 each "D" cell batteries
BATTERY LIFE: Typically greater than 2000 hours with alkaline batteries
METER: 2.5" (6.4 cm) arc, 1 mA analog type
CONSTRUCTION: Cast and drawn aluminum with beige polyurethane enamel paint
TEMPERATURE RANGE: -4°F(-20°C) to 122°F(50°C)

Probe info

Specifications

INDICATED USE: alpha, beta, gamma survey; sample counting
DETECTOR: pancake-type, halogen-quenched GM
WINDOW: 1.7 + 0.3 mg/cm² mica
WINDOW AREA: 15 cm² (2.3 in²) active, 12 cm² (1.9 in²) open
EFFICIENCY (4π): 5%-14C; 22%-90Sr/90Y; 19%-99Tc; 32%-32P; 15%-239Pu,  ≤  1%-99mTc; 125I-0.2%
SENSITIVITY (137Cs gamma): 3300 cpm/mR/hr
ENERGY RESPONSE: energy dependant
BACKGROUND: 60 cpm
DEAD TIME: 80 microseconds
OPERATING VOLTAGE: 900 Vdc
CONNECTOR: series "C" (others available)
INPUT SENSITIVITY: ≥ -30 mV
CONSTRUCTION: aluminum housing with beige powder-coat finish
TEMPERATURE RANGE: -15 to 50 °C (5 to 122 °F), may be certified for operation from -40 to 65 °C (-40 to 150 °F)
SIZE: 4.6 x 6.9 x 27.2 cm (1.8 x 2.7 x 10.7 in.) (H x W x L)
WEIGHT: 0.5 kg (1 lb)