Block-IR infrared heat shielding keeps the heat where it belongs! The technology behind this energy-saving sheeting originated at N.A.S.A., and now non-astronauts can use it to keep their indoor gardens from wasting ambient heat. Block-IR consists of two layers of infrared-blocking material bonded with polyurethane, which surrounds a core of non-conductive insulation. When sealed with foil tape, it creates a barrier that locks heat in. 100-foot roll.