Fluidmaster 8100P8 Toilet Bowl Cleaning System, BlueFlush n'sparkle puts a cleaning solution directly into the overflow tube of the flush valve, so no chemicals ever touch the flapper or fill valve. This prevents the damage that a drop in tablet normally inflicts while keeping the bowl clean and sparkling. The 8100 kit contains a blue cleaning solution that lasts up to three months. Replacing the cleaning solution cartridge takes less than a minute. Unit: CD UPC: 039961880017 Model Number: 8100P8