Insul-SHIELD® is a series of semi-rigid or rigid thermal and acoustical fiber glass insulating boards for custom curtain wall applications. They are made from inorganic glass fibers bonded with a thermosetting binder. The insulating boards are typically used where framing is not present. Faced Insul-SHIELD boards (FKS-25, PSK or Black Faced) can be used where a vapor barrier is needed. FSK facing has the best fire performance characteristics and helps maximize lighting efficiency. Insul-SHIELD Black provides a semi-rigid substrate beneath the fabric treatment used on theater side walls. The black, mat-faced insulation provides adequate shadowing behind any surface treatment.