Fit for Litter Robot Filter: The Cat litter filter only compatible with Litter Robot 4,Please check the model number before purchasing filter fit for litter robot 4 filter 2xThickened and : Our replacement filter is made of fiber activated carbon with millions of microscopic pores that increases high adsorption for better filtration performance. 2x thicker than your average filters, reduce unpleasant odor efficiently and continuously Keep Home Fresh and Clean: Charcoal filters for cat litter box can effectively absorb odors, Activated carbon filters improve indoor air quality by absorbing the peculiar smell in the cat litter box 8-Pack of Cat Filters: Litter box deodorizer filters provides 8 months of odor control, And we recommend changing the cat litter box filters fits litter robot carbon filters monthly Easy to install: No tools required. No measuring or trimming needed. Simply lift the lid of the litter box and swap filter fit for litter robot 4 carbon filters out Color: Black Material: Activated Carbon Package Contents: 8 * Carbon Filters Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.