The Fresha Flush Microbial Disc is a silver disc placed in the cistern of a toilet. It destroys germs, reduces limescale build-up & provides a sterile flush every time. Made from natural materials, the environmentally friendly silver disc is everlasting so there is no need to ever replace it. One should be bought per cistern/toilet. The Fresha Flush disc uses the same industrial silver you would find in drinking water purifiers & hot tub filters & uses the natural effects of real silver that when immersed in water kills germs, bacteria & water borne diseases. It also has a strong ultra-neodymium magnet which crystallises limescale preventing limescale forming on toilet surfaces. Water therefore stays fresh, preventing the need to bleach toilets which has a positive impact on the environment & in the long run saves you money. The high-quality disc is both incredibly effective, reliable & hygienic & abides by European standards.