Antifreeze Protector Alphi-11 5 Litre (Product Code: 61033) is a premium combined antifreeze and inhibitor solution, designed to protect domestic central heating systems against internal corrosion and limescale. Suitable for all common system materials, Alphi-11 ensures long-lasting performance when concentration levels are maintained annually. Protects to -11°C at 25% concentration and to -22°C at 40%. Easy to apply and compatible with all Fernox products.