Nulon REBSL-500 Radiator and Engine Block Stop Leak with DuPont Kevlar fibre and liquid resin provides the ultimate strong long lasting fix. Formulated to permanently seal radiator leaks, inlet manifolds and engine block leaks, cracks, leaking welch plugs and leaking gaskets without costly mechanical repair. This unique microfibre technology seeks out and plugs small leaks and cracks that cause coolant loss, loss of pressure and overheating. It can be safely used in cars, trucks, vans, utes and light commercial vehicles. Safe for all plastic, aluminium and metal radiators, heater cores, gaskets and welch plugs. Safe to use with all types and color of glycol anti-freeze/anti-boil and water based coolants. Comes in 500 ml.