These Granulated Bamboo Charcoal replacement filters are much more effective than the plastic mesh type that come with most compost pails. Each packet holds 80 grams of activated carbon derived from environmentally friendly bamboo. Activated Carbon is a natural air purifier, and has a surface area as high as 600 sq meters per gram, and is excellent at absorbing and trapping bacteria and odors. To use, just place one packet in the filter compartment of your compost pail. These 5 1/2" round filters fit many different brands, don"t worry, the fit doesn"t have to be exact for them to work, the granulated bamboo charcoal absorbs and traps the odor of anything that"s nearby. These can be re-used for up to 1 year, but for best results, we recommend that you replace them twice a year. Once they have been exhausted, you can cut them open and add to your compost, or spread the charcoal on your garden or lawn to enhance the moisture retention of your soil. To keep them working at their best, just lay the bags out in bright sunlight for a couple hours twice every month to regenerate their odor absorbing power. These Bamboo charcoal filter bags are multi-purpose, and can be used anywhere you have an odor problem. Customers have told us that they use these in their closets, bathrooms, and laundry rooms as well as near litter boxes to help control pet odors. These are available in 2 colors to keep them separate if you"re using them in multiple locations. Search amazon for "Thinkbamboo-charcoal" to find more bamboo charcoal odor absorbers.