Now, with germ fighting technology, the active zinc hook on this Harpic Toilet Block inhibits the growth of bacteria for a hygienic cage-less toilet solution. No cage, no mess. Harpic Germ Fighting Technology uses a blister made from 70% recycled plastic. It's convenient design fits seamlessly under the toilet rim to help fight odours and provide lasting freshness. The easy way to maintain a clean, fresh & fragrant toilet with every flush! Contains a germ fighting active zinc hook. Leaves a lasting fresh fragrance Blister made from 70% recycled plastic Convenient design fits seamlessly under the toilet rim.