Fernox Protector Alphi-11 is a combined antifreeze and inhibitor, which gives long term protection of domestic central heating systems against internal corrosion and limescale formation. It prevents corrosion of all metals found in these systems, i.e. ferrous metals, copper and copper alloys and aluminium. Fernox Protector Alphi-11 is compatible with all metals and materials commonly used in central heating systems. For continued protection we recommend Protector levels are checked regularly (annually). The concentration of the product can be easily measured on site using a Fernox Protector test kit. Protects against corrosion and limescale. Maintains efficiency so extending system life. Compatible with all metals and materials commonly used in heating systems. Non-toxic, environmentally friendly. Combined antifreeze and protector.