This set is an option to the afr tuning monitor.It allows you to install a pair of wide band sensors on all exhausts where it is not possible to simply replace the installed o2 sensors (m18 thread).The set contains a powerful double pump, which ensures high accuracy and measurement speed of the actual afr in each cylinder.The pump is powered by a 12v supply and can therefore also be used for road testing.An open pipe adapter is available to extract undiluted exhaust gas farther up the pipe.