Scalemaster Magnetic Limescale Inhibitor Scalemaster Gold 22mm Compresson Magnetic Limscale Protector Metal Body - no earth bonding necessary Scalemasters require no power source or chemicals Large cathodic area giving superior performance Universal and for domestic use Scalemaster Inhibitor suitable for protection of individual apppliances such as combi boilers, dishwashers and showers etc No moving parts, no maintenance requied 3 year guarantee