Kilrock Big-K Descaler 400ml is the original multipurpose descaler. The powerful formula eliminates limescale in kettles, shower heads, steam irons and WC pans. It's phosphate free and 100% biodegradable. Always read the label. Banish limescale with Kilrock Big-K Descaler! This 400ml bottle of powerful, multipurpose descaler tackles limescale build-up in kettles, shower heads, steam irons, and toilet pans. It's phosphate-free and 100% biodegradable, making it an environmentally friendly choice. Remember to always read the label. Destroys limescale in minutes. Ideal for metal and plastic kettles, steam irons, and WC pans. Phosphate free. Biodegradable.