Bio-Production Royal Flush Cistern Blocks deliver both biological and chemical cleaning agents as well as a blue coloureach time the flush is activated. The water-softening and sequestering agents maintain a clean bowl while the biological cleaning power works in the pipes to prevent any build-up of solids and continues working in small bore, pumped toilet systems and older buildings where drain-runs can be problematic. Also enhances septic tank efficiency. Bio-Production Royal Flush Cistern Blocks rapidly degrade organic solids & 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. Bio-Production Royal Flush Cistern Blocks Features: - 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 benefi