This temperature slightly depends on the fuel to oxygen ratio and strongly depends on gas pressure – there is a threshold below which cool flame is not formed. A specific example is 50% n-butane–50% oxygen (in volume percent) which has a cool flame temperature (CFT) of about 300 °C at 165 mmHg (22.0 kPa). One of the lowest CFTs (156 °C) was reported for a C2H5OC2H5 + O2 + N2 mixture at 300 mmHg (40 kPa).[10] The CFT is significantly lower than the auto-ignition temperature (AIT) of conventional flame (see table[8]).[2]