Internal leak sealer developed for use throughout a central heating system to seal microscopic, inaccessible leaks and weeps which may cause pressure loss and boiler breakdown. Saves time and money on draining down the system and repair costs. Does not cause blockages in pipework or vulnerable boiler components such as pumps, air vents and heat exchangers. Compatible with all metals and materials, including aluminium. Designed to be left permanently in the system. One bottle treats a 130Ltr system, up to 16 radiators, or 250m² of underfloor heating. 1 Year Guarantee Fixes System Pressure Loss Quickly Concentrated Fast-Acting Formula 1 Year Guarantee Fixes System Pressure Loss Quickly Concentrated Fast-Acting Formula