TO OUR FIREMASTER FASTWRAP XL. MORGAN THERMAL CERAMICS. DUCT ENCLOSURE SYSTEM. FLEXIBLE BLANKET COMPOSED OF HIGH. 3M PRODUCT 615+24 FIRE BARRIER DUCT WRAP THAT IS EQUAL. A GOOD SUBSTITUTE FOR. 1-1/2 THK X 24″ WIDE X 25 FEET LONG PER500 SQ FEET PER ROLL.