Antifreeze Protector Alphi-11 is a combined antifreeze and inhibitor product, which provide protection against internal corrosion and limescale formation in domestic central heating systems . Available in 5 litre and 25 litre liquid product. Antifreeze Protector Alphi-11 is suitable for use with all metals and materials commonly used in heating systems. For long -term protection ensure concentration levels are maintained and checked annually as part of the boiler or system service. Antifreeze Protector Alphi-11 is compatible with all other Fernox products.