Effectively create return air ducts between joists or studs with this Imperial Joist Panning Lining. The 16-1/12" x 30" joist lining seals the underside of floor joist space, creating a duct run to channel air back through the air return system. This allows you to nail or screw the lining directly into the wood, creating a run of rectangular duct. The panning lining is constructed from 30-gauge galvanized steel for rust resistance and lasting durability. It can be cut to size to fit a variety of applications, and is easy to install with sheet metal screws for a secure fit (screws sold separately). This joist panning lining is suitable for use in most heating, venting and air conditioning applications.