High-density black fiberglass tissue is characterized by a higher concentration of glass fibers per unit volume, resulting in greater strength and durability. This type is often used in applications requiring high mechanical resistance, such as in aerospace or automotive components. Low-density black fiberglass tissue, on the other hand, has fewer glass fibers per unit volume, making it lighter and more flexible. It is commonly used in applications where weight is a concern, such as in the electronics industry for insulation or in construction materials. The main differences lie in their mechanical properties, thermal conductivity, and applications.