They are low-temperature insulation materials. Though the most common paper in this category is kraft paper, The Gund Company offers a wide variety of material options.

Aramid fiber paper is characterized by exceptional temperature and tear resistance. This includes but is not limited to aramid papers, such as Nomex® and 3M® inorganic paper products. These papers can be formed into basic shapes to help line slots or make fitted bends on corners. Papers made from inorganic fiber are less expensive than aramid fiber papers and have better thermal conductivity. Typically, they are more brittle and can only be formed reliably when used as a laminate with a thermoplastic film.