Royal Flush Cistern Blocks rapidly degrade organic solids and continue working after discharge into the sewer or septic tank, preventing odours & blocked drain-fields. Regular use of Royal Flush ensures the toilet system remains trouble free. Biological formulation. Cleans, deodorises and freshens toilet bowl with each flush. Keeps systems clean and odour free. Helps to prevent blockages and limescale. Long lasting. Lightly fragranced for optimum benefit. Contains germicide. Helps prevent limescale. Pack of 24 blocks. 50kg tub. When not in use, keep closed in the original container. Keep out of the reach of children.