Kalstop is a product of plant origin, not harmful to human health, readily biodegradable and harmless to the environment. It helps prevent limescale build-up for longer boiler life, improves steam emission, and helps appliances run more efficiently. This package contains 20 x 5ml phials. Suitable for use with Polti Vaporella Steam Generators, Irons, and Vaporetto Steam Cleaners.