This patented Mercury flushing system fits MCM/MIE 4.3L, 5.0L, & 5.7L (Gen +) engines with drainable circulating pump hose. Although the product seems relatively simplistic, this patented product is the only known "Non-Engine Running" method of flushing an engine while actually clearing out both sides of the thermostat: exhaust manifolds and engine block. Most "Non-Running" engine flush setup will only flush out the manifolds due to the thermostat closing once cold water is introduced, and therefore preventing flushing of the block itself. If your engine does not have the 3 piece circulating pump hose including the "Blue" drain fitting, you will need to order the following hose setup to allow use of this flush system. Link to Hose...