This is the first test run of a 31 cell series electrolyzer design. It produces HHO gas, a mixture of oxygen and hydrogen. The gas is uses as it is produces so there is little danger. I was able to get a MAX of 41 MPG on my 4 cylinder 2000 plymoth voyager van. I was also injecting water vapor and offsetting the voltage on the oxygen sensor to allow t he computer to trim fuel injection. This is the same design that high efficiency water torches (HHO/browns gas) use. I also lit the gas just to watch it burn.