NIST 2025 Calibrated! Ludlum Model 3 + 44-6 Probe Guaranteed for 1 year!

Calibrated meter and probe combinations are available for purchase or rental. Contact us if you need a specific configuration.

This Ludlum Model 3 paired with a Ludlum 44-6 gamma probe has been fully serviced and calibrated using a Ludlum Model 500 digital pulse generator with a current NIST traceable factory calibration. The 44-6 is an energy-compensated GM detector designed for gamma count-rate measurements. The meter features a CPM-only scale face, and its needle response and output were verified following Ludlum calibration procedures. Calibration paperwork documenting the December 2025 service is included.

Certified 2025 Calibration
Ludlum Model 3 Survey Meter with 44-6 Gamma Detector

This unit is fully functional, tested, and ready for immediate use. Batteries are included.
You will receive the exact instrument shown in the photographs.

The meter is used and may show normal cosmetic wear from handling, but it has been inspected, serviced, and adjusted to ensure proper performance. All calibration documentation shown in the photos is included.

CPM-only display for gamma count-rate measurements
Ludlum 44-6 energy-compensated GM probe for gamma detection

The photos show the probe responding to a check source to demonstrate proper function. The check source is not included.

These are high-quality professional instruments that have been maintained and tested to a very high standard.

Please review all photos and feel free to search the part numbers for additional details and specifications.

If you have any questions, feel free to reach out. I respond quickly.

Item ships the same day payment clears.

If purchasing from outside the 48 states, please contact me before buying to arrange shipping.