Monitor Instruments, Inc.
Monitor Instruments, Inc. is a manufacturer of industrial audiometers and audiometric accessories, offering quality instruments and professional calibration services for audiometers and acoustic safety equipment since the early 1970's.
(800) 853-6785  ·  (919) 732-5400  ·  FAX (919) 732-6153  ·
The MI-300 Calibration Monitor

The MI-300

The MI-300 Calibration Monitor performs a quick and efficient daily biological calibration check of your audiometer, as required by OSHA. Its lightweight and durable construction will insure years of trouble-free operation.


  • LED indicators for right response, left response, and power on.
  • Calibration at 70 dB hearing level at 1 kHz.
  • Both normally open and normally closed response relay configuration.
  • Automatic power off when not in use.
  • Designed for wall mount or table top use.
  • Works with manual or automatic microprocessor audiometers.

General Description

  • Power: 9 volt alkaline battery
  • Size: 6.0 x 6.0 x 3.3 inches
  • Weight: 1.0 lb.
  • Construction: Aluminum housing with delrin coupler.

Standard Accessories

  • 9 volt battery
  • Response cable (specify make and model of audiometer when ordering)
  • Rubber feet
  • Operator guide

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