ThinkBamboo Round Replacement Carbon Filters for Compost Bins - 4pc, Blue 4 pack Round Replacement filters for compost pails. Each contains 80 grams granulated bamboo charcoal. Each measures approx 5 1/2" (14cm) across and 1" (2.5cm) thick. Fits in the filter compartment for many different brands of compost pail, and is much more effective than the stock mesh type filter. Re-usable, to recharge the odor absorbing and destroying power of the bamboo charcoal, simply lay the non-woven filter bag out in bright sunlight. Multi-purpose, these bags of granulated bamboo charcoal can be used anywhere you have an odor problem. They work great in the refrigerator, or taped inside the lid of your trashcan.