Taste your coffee not the limescale nobody likes taking in a moutful of chunky limescale with the magic ring in your coffee machines water tank your coffee tastes even better this water softner reduces the negative effects of hard water such as mineral build up bad tasting water clogged piping and filters applications humidifiers toilet tank coffee machines water tanks and more diameter 5 cm note not suitable for direct contact with heating coils eg in the electric kettle