Fga's are mainly used for co/co2 ratio's. i know they can be used for temp & pressure readings but we can use thermometers & u gauges for that. Lets be honest about it these analysers with there initial & maintenance costs are a nice little earner for the company's. When you think about it, you can buy a co detector for next to nothing and it surely can't be that difficult to record the co2. Somehow i think we are all being taken to the cleaners there. So my question is, is there another way of checking co/co2 without using a fga ie a simple co/co2 reader. If there's not, there;s a fortune to be made by any budding inventor.