This low height hidden toilet cistern has been specially designed to be water saving with back to wall toilets. Each eco concealed toilet cistern can save up to 25% of the water compared to a standard cistern. This dual flush in wall cistern conserves water on the main flush using 4.5 litres instead of 6 litres with the half flush still the standard 3 litres. Being restricted in height this low toilet cistern is ideal for under windows and other height restricted areas."extremely reliable cisterns"