EFFECTIVE BLEACHING: Containing powerful bleaching ingredients, Vacplus toilet bowl cleaner tablets can efficiently eliminate urine scale, limescale, rust stains, and other stubborn dirt while with every single flush. Keeping your toilet bowl sparkling and clean is what Vacplus is doing! LONG-LASTING EFFECT: Enjoy an effortless and long-lasting toilet cleaning with just 1 purchase! With sustained-release technology and an upgraded formula, each Vacplus toilet tank cleaner tablet can continuously clean and freshen the toilet bowl for about 18 days. With 12 packs for replacement, these toilet cleaners can help to maintain the luster of your toilet bowls for up to 31 weeks.