Model 221R Oxygen Deficiency Monitor

The Model 221R has become the standard oxygen deficiency monitor throughout the US market. 

It is used by the thousands in government labs, universities, and industry, anywhere there is a possibility of asphyxiation due to leakage of compressed or liquefied inert gases like nitrogen, argon or carbon dioxide. 

It has become the standard because it is extremely reliable, does not drift even with extreme temperature swings or barometric pressure changes and does not generate false alarms but responds very rapidly to real oxygen emergencies.

Competitive monitors that use conventional electrochemical sensors suffer from serious false alarms issues. 

Electrochemical sensors lose sensitivity over time – requiring monthly calibration - and typically after about a year need to be replaced. 

These sensors suffer from pressure and temperature sensitivities that cause them to drift into alarm when weather patterns change or even when air conditioning systems cycle, even though the actual oxygen level is safe.