40-0009051 Water tube, For G3400, D 3400 G 2300, D2300 series Hercules engines. In line radiator tee/access point for block heaters or coolant level swith40 0009051 Tee to access the coolant system on any model of engine whether for a Hercules engine or any other brand of engine. The O. D. of the tube is 2 inches and the small threaded outlet is 1 2 inch NPT This is a adaptive hose product that can be used in any application, doesn't have to be only a engine purpose.