1. Eco-friendly no phosphorus and heavy metal. 2. The utility lastingwater temperature in the below 25 degrees can be used 200 times. 3. Contains active substance to clean and freshen your toilet bowl automatically. 4. Prevent filth form accumulating on the bowl wall by forming a protective layer. 5. Safe for use with toilet bowl. It is very necessary for modern family life. 6. Remove the cistern cover. Drop the block to the bottom of the cistern with tow sides against the cistern wall near the float but away from the water inlet and keep it still in order to ensure it long lasting. 7. One piece could be used for 15 days add a new Toilet Bowl Cleaner when the blue color of flushing water disappears.