Lang Tools (TU-32-20) Fuel System Pressure Test Gauge is for use on Compuchek test ports on the fuel system of Cummins diesel engines, as well as other diesel engines that have been outfitted with the Compuchek test ports. The TU-32-20 contains a hose assembly with a female Compuchek fitting on one end and a 3-1/2", 300 PSI gauge on the other.