Official Size for LR3: 3.5 x 10 x0.5 inches and built in activated carbon, this carbon filter great for absorbing odors and controlling moisture in the waste drawer. More Activated Carbon: Each filter contains as much as 150 grams of activated carbon to cover more area. This makes them highly absorbent and more effective in soaking up odors and moisture. Healthy Material: These kitty litter box filters contain natural activated charcoal made from coconut shells and wood. They're made without the use of powders, sprays, or fragrances. Seconds Installation: No tools required. No measuring or trimming needed. Just remove the old filter and insert these new filters and you're done. These filters are compatible with Litter Robot 3. 8 Packs: The package includes 8 self cleaning cat litter box filters. Depending on the number of cats in your home and their frequency of use, each filter can last for up to 6 months. For best results replace every month.