Harpic Flushmatic toilet cleaning cistern block is a drop-in tank tablet which can be used for any accessible cistern. It works by creating strong foam every time you flush the toilet, which helps to maintain cleanliness in the toilet bowl. Harpic Flushmatic toilet cleaner works from inside the cistern to release a dose of powerful detergent with every flush. Distributing the liquid across the bowl, it helps you maintain a hygienic and fresh toilet and prevents the build-up of stains giving you a continuous clean toilet.