Fiberglass duct board is a rigid board of insulation material manufactured from resin bonded inorganic glass fibers. 

The exterior surface of the board is a factory-applied reinforced aluminium foil-air barrier and water vapour retarder. 

The edges of the board are formed by machine to create a ship lapped edge or grooves, to allow the grooves to be joined to build straight ducts of any size or length. Duct system components such as tees, offsets, elbows and transitions may be fabricated from flat duct board. Fibrous glass duct boards are fabricated into ducts to make a fibrous glass duct system.

Fireproof aluminum foil glass wool board