These Saddle Air-Tite Take-Offs are used to transition from a round surface to 6 in. round pipe or 6 in. insulated flexible duct. Quality construction makes these take-offs easy to install and long-lasting. The Tacky gasket provides excellent seal.Tacky gasket creates a secure, substantially air-tight sealAlways seal seams with code approved mastic or sealant or duct tapeInstall with sheet metal screws not includedAlways insulate ductwork for greater system efficiency and comfort