The RAM 4021 AutoCal^® series is the unit of choice where specific and accurate measurement of carbon monoxide, oxygen or dew-point levels are required.  Designed to meet OSHA requirements for monitoring Grade D respirable air, this unit is equipped with a reliable electrochemical sensor that accurately indicates the level of carbon monoxide on an illuminated liquid crystal display.  Adding versatility, this unit offers optional oxygen or dew point sensors for applications where detection or measurement is needed.