This is MG Chemicals Polyimide Tape (POL100-15). It is a very lightweight and flexible tape at only 2 mils thick. This is a crystalline film with a silicone adhesive that is specially designed for 3D printers heated beds. The Tape works works great in low temperatures and doesn't soften when submitted to head. It also has a superior release surface at elevated temperatures. This polyimide tape has excellent tension strength, good elongation, and is chemical resistant. The tape comes in 4" width in a 49 Foot roll.