For residential retrofit, particularly in the attic laying over existing insulation, and some OEM applications. Available in 500 and 1,000 sq. ft. rolls or custom lengths. Super Shield NASATECH brand radiant barrier was the first product developed by US Energy Products. Super Shield 51inch Rafter Friendly Size is a two-sided reflective aluminized polyester film with reinforced scrim inside, designed to reflect radiant heat no matter what the season. Choose Super Shield 51inch Rolls to retrofit an existing structure where 48 inch rolls are just too short. It can be stapled to the underside of the roof rafters in an attic and ideal for 24inch overlaps. Meets ASTM C1313 Standard Specifications for Sheet Radiant Barriers for Building Construction Applications WE USE EBAYS UNPAID ITEM.