Johns Manville's 800 Series Spin-Glas® equipment and external duct insulation provides a broad range of solutions to meet your unique application needs. The breadth and depth of our product availability includes plain, FSK, AP (ASJ), or Ultra (poly-top) faced board, where the facing acts as a vapor retarder. You can be assured you are getting the same superior performance from the facing as the insulation because we manufacture both to the highest quality standards. Johns Manville's 800 Series Spin-Glas board is easily fabricated for an excellent finished appearance on duct and equipment systems.