Litter Pearls unique blend of Probiotics is designed to be MIXED IN WITH ANY LITTER SUBSTRATE to achieve the best possible odor control! Our Probiotics stay dormant (asleep) inside the Silica Gel Crystal vessel until activated by pet waste. Once activated, our Probiotics 'wake up' and begin to colonize and consume all possible food sources before foul, odor causing bacteria have a chance to stink up your home. Silica Gel Crystal provides the perfect delivery method for these Probiotics to thrive while keeping you litter box completely odor free. Just stir in the 500g pouch to any existing (clean) litter substrate and maintain daily maintenance. Your home will smell great and your nose will thank you!