A Duct Muffler can make indoor gardening fans significantly quieter, and can reduce noise heard from room to room. The 6" Duct Muffler is for use with 6" ductwork and reduces noise by up to 23 dBA; a reduction by 3dBA cuts a listener's perception of sound by half! These Duct Mufflers are easy to install, connect to existing ductwork, don't restrict airflow, and require no maintenance. Support brackets not included. The item has a 1 year manufacturer's warranty.