The 3000SI range includes (but is not limited to) CO, O2, NH3, Br2, NO2, H2, SO2, O3, HCN, F2, ClO2, H2S and Cl2 all providing a 4-20mA output.
Analox realise that not all customers require a complete monitoring solution and prefer to integrate sensors into their own system. The 3000SI range is ideal for this requirement if analogue inputs are required.
The 3000SI range is small enough to be integrated almost anywhere in your Laboratory breathing air system.  Each of the housing has a gas port and using a simple flow adapter they can easily be installed in series in the gas path. They are also sometimes used on the inlet to the compressor, particularly where H2S and NH3 are a concern. 
With a Zone 0 rating they can be used in almost any environment and are commonly used on platforms, chemical plants or integrated into vapour emission systems.