Seals leaks in vehicle cooling systems. Inhibits rust and corrosion. Prevents scale build up in pipes and radiator. Lubricates water pumps. Safe with all anti-freeze/coolant solutions. Harmless to all plastic, aluminium and other metals rubber hoses& connections. Will not cause blockages in the cooling system. Rislone Radiator Stop Leak Cooling System Supplement Tablets are the easiest way to stop cooling system leaks while simultaneously maintaining the cooling system in optimal condition and performance. These are the same formula tablets supplied to many OEM auto and truck manufacturers around the world. Rislone Radiator Stop Leak Tablets are formulated to inhibit the formation of rust and scale, neutralise pH imbalance of cooling system fluids, control electrolysis, lubricate and seal internal, external and coolant-to-oil leaks. One tablet treats 3 to 3.5 litres of coolant. Use additional tablets for larger capacity cooling systems.