The 803 type protable oxygen detector is a kind of essential safety instrument which can continuously detect the oxygen concentration in the working environment. It is suitable for explosion-proof,toxic gas leakage, underground pipelines or underground mines and other places, can effectively ensure the safety of the staff's life is not infringed.This instrument is a natural diffusion method for detecting gas concentration,using high performance electrochemical sensor, with excellent sensitivity and excellent repeatability. The instrument adopts embedded micro control technology, simple operation,complete functions,high reliability. This product is applicable to the concentration of oxygen in the ambient air detection,are widely used in metallurgy,power plant,chemical,mine,tunnel, underground pipelines and other places,effective prevention of hypoxia and oxygen poisoning.