Block-IR infrared heat shielding keeps the heat where it belongs! 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 the heat in. Rolls are 4ft wide. Infrared blocker can be used to keep a grow space discreet by preventing the leakage of infrared light.