4pcs Automatic Tank Cleaner Chemical Free Magnetic Toilet Bowl Cleaner for Hard Water Stains Long Lasting No Chemicals No Staining

Great for areas with hard water Set of 4 toilet magnets 4-1/2"L each Helpful Hint: If you have very hard water, you can remove the magnets, rinse and wipe them with a paper towel. Then reinsert them into the tank. They can also be used in humidifiers.