Solid conduit plugs are used to seal auxiliary holes in ducts. Expansive rubber is sandwiched between two steel disks joined by a carriage bolt. As the bolt is tightened the rubber expands creating a seal around the diameter. A tab is provided to secure a pulling rope for future use.
Split rubber plugs are used to seal the ends of ducts occupied by cables. The rubber has a diagonal slit to allow its placement over cable. Sealing occurs as the rubber is compressed by tightening of carriage bolts which extend through steel segmented plates on either side of the rubber gasket.
Plugs are designed for the nominal duct and cable size and for either square or round duct.