The OdorHog eliminates odors as they exit the vent stack, allowing you to enjoy an odor free back yard/patio. This style carbon filter installs directly onto plastic PVC or ABS vent pipes. The majority of homes and buildings today have plastic pipes. Filters for metal, copper or cast iron pipes are available on our website, not on Amazon. OdorHogs are made from HEAVY DUTY SCHEDULE 40 PVC AND ABS. They are made to stand up to the harshest climates and storm conditions. They are not made from thin, plastic injection molded parts from China like other filters. OdorHogs come with the highest quality pelletized carbon in a replaceable, breathable mesh bag, that can be easily changed out while the filter remains on the vent stack (no dirty mess like change outs on other filters). OdorHog activated carbon is formulated for the H2S molecule and made to last. We include a freeze protectant to keep the carbon from freezing in cold climates. The additive is similar to salting your walk or driveway after a freeze or snow. It coats the carbon and keeps it from sticking together. Slip on cuffs require no glue or tools. Snug it on and give it a twist. Don't be fooled by claims that other filters contain "more charcoal". The carbon has to be high quality to last years, more is not better when it contains charcoal shards and small particles that quickly breakdown and can clog the filter and vent pipe. Proudly made in the USA. OdorHog has been in business for over 18 years and is the leader in vent pipe filters. Email or Contact Odorhog with any questions. We're also happy to help with sizing questions.