Johns Manville insulation;GREENGUARD certified insulated products;Galvanized or bronze metal core reinforcing;Oversized core to fit on collars and register boxes;Weather-resistant packaging;Easy-to-carry package: Up to 10" bags are strapped to form a pair;Available in boxes and bags;12.5', 25', 50' and custom lengths available;HUD /FHA standards 515.2.1, paragraph B;NFPA standards 90A and 90B;Meets most BOCA, City of Chicago, federal, state and local codes and standards;UL listed/approved to UL 181