K&H Pet Products Replacement Filter Cartridge 3 pack Small Black 3.5" x 2.25" x 2" K&H Pet Products Sale! from $4.59 Qty. Add to Cart This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Features: Filters contents up to 130 times per hour. Charcoal filter helps remove impurities.