This is a telescoping adjustable motor flusher for inboard boat motors. It allows the cooling system to be flushed out using a garden hose, and it works on most inboards. It has a great way to test run your boat before heading for the water. You can install in seconds using just a water hose, and flushes the motor every time you use your boat to help keep salt, grim, silt, and sludge off the internal parts your motor while the boat is on the trailer. No tools required. Soft, rubber cup for proper circulation and also prevents scratching. Telescoping flusher installs in minutes. Adjusts from 18 to 30 inch with just a twist. Large cup prevents water blow by or fall off during usage or flushing. For use on gas or diesel inboard engines with thru hull water intakes. Telescoping tube allows precise alignment for hard to reach areas.