Cleans with every flush! Up to 6 months of cleaning! 100% tough! Constant cleaning action prevents: ring around the toilet; rust; hard water stains. Works with Kaboom Scrub Free! Continuous Toilet Cleaning System. Quick to refill! Kaboom Scrub Free! is a revolutionary automatic toilet cleaning system that easily attaches out of sight within your toilet tank. It injects a powerful cleaning formula into the toilet bowl with every flush, keeping it clean, even under the rim! Won't harm tank parts (like drop-in solids or pucks). Refillable. Safe for septic systems. Cleans & deodorizes. Repels stains. Go scrub free! Up to 6 months of cleaning!