Epilay™ Ultra ProtecTite™ Roofing Underlayment with its advanced engineering is highly recommended for mechanically attached, coated woven synthetic roofing underlayment for sloped roofs. Epilay™ Ultra is specifically manufactured to replace the 30# felt. Epilay™ Ultra is 25 times stronger than 30# felt and 4x lighter than 30# felt. With a 11 mil thickness a 10 square roll weighs only 29 lbs! This super low weight combined with 48" width and 250 ft. run length means big savings in time and labor (over 30% faster to install than felt!). These unique design features when coupled with Epilay™ Ultra's exceptional light weight and exceptional tear strength allows the contractor to easily carry the roll up and down the ladder. Fewer laps, cuts and roll handling means you can do more jobs in less time resulting in huge savings for you, the roofing contractor.