*Without Auto Alert Function.

The CRM-100™ is a general purpose geiger counter that measures alpha, beta, gamma, and x-radiation. It is intended for personal safety and educational purposes. Like the popular Radalert 100™, the CRM-100™ features a 3-second update on its digital liquid crystal display (LCD). The LCD shows the current radiation level in your choice of milliroentgens per hour from .001 to 110 or counts per minute (cpm) from 0 to 350,000. When SI units are selected, the LCD shows readings in microsieverts per hour from .01 to 1100 or counts per second (cps) from 0 to 3,500. This instrument also offers an accumulated total and timer function, up to 9,999,000 counts and 40 hours. A red LED blinks and a beeper chirps with each count (the chirp can be muted).




  • Halogen-quenched Geiger-Müller detector (LND712)
  • Mica end window density is 1.5-2.0 mg/cm²
  • Side wall is 0.012″ #446 stainless steel
  • Detects Alpha, Beta, Gamma, and X-radiation


Display:4-digit liquid crystal display with mode indicators


  • Accuracy:±10% typical; ±15% max. (mR/hr and µSv/hr modes)
  • Alert:No Alert feature. If your intended application requires a user-adjustable Alert, we recommend the HAC001 Radalert 100™
  • Audio:Beeper chirps for each count (can be muted)
  • Calibration:Cesium 137 (gamma)
  • Certifications:CE Certified, RoHS Compliant, and Meets WEEE standards
  • Count Light:Red LED flashes with each count
  • Designed & Manufactured:Designed in USA by International Medcom, Inc. Manufactured in Thailand under ISO 9001:2001 & ISO 14001 Certification
  • Operating Range:
    mR/hr: .001-110 CPM: 0-350,000
    µSv/hr: .01-1,100 CPS: 0-3,500
    Total: 0-9,999,000 counts Timer: up to 40 hours
  • Options:Computer cable and software (Windows compatible)
  • Ports:
    • Output: Stereo 3.5 mm jack sends counts to computers, data loggers, other CMOS-compatible devices, and headphones
    • Input: Mono 2.5 mm jack provides electronic calibration input
  • Power:One 9-volt alkaline battery; average battery life is 2160 hours at normal background, 625 hours at 1 mR/hr with beeper off
  • Sensitivity:1000 cpm/mR/hr referenced to Cs-137
  • Size:150 x 80 x 30 mm (5.9″ x 3.2″ x 1.2″)
  • Weight:225 grams (8 oz) including battery





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