Bars Leaks has millions of tiny particles to permanently seal leaks in plastic, aluminum and metal radiators, heater cores, blocks, heads, gaskets and freeze plugs. Compatible with all brands of antifreeze, including extended life (green and orange). Lubricates water pump seal and inhibits the formation of rust and scale. Same patented concentrate as used world wide by car and truck manufacturers to protect vehicles against cooling system leaks. Use two tablets per gallon of coolant.